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Sample records for chukchi sea

  1. Bathymetric Map of the Bering/Chukchi Sea

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Two bathymetric maps were developed by the U.S. Geological Survey, one for the Chukchi Sea and Arctic Ocean, and one for the Aleutian Trench and Bering Sea. The 2...

  2. REE geochemistry of surface sediments in the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    陈志华; 高爱国; 刘焱光; 孙海清; 石学法; 杨作升

    2003-01-01

    Analyses of rare earth elements (REEs) in 26 surface sediment samples obtained from the Chukchi Sea were conducted using ICP-MS. In general, REEs are relatively rich in fine-grained sediments and deplete in coarse-grained sediments in the Chukchi Sea although REEs have large concentration spans in different types of sediments. Except that a few samples have weak enrichments of light or heavy REEs,most samples exhibit flat shale-normalized REE pattern, indicating that surface sediments in the Chukchi Sea are composed dominantly of terrigenous components experiencing weak chemical weathering. In terms of REE concentrations and other characteristic parameters, we inferred that sediments on the eastern and western sides of the Chukchi Sea are derived from landmasses of Alaska and Siberia, respectively; the midsouth sediments are possibly related to northward dispersion of the Yukon River materials. The Herald Shoal in the center of the study area is covered with relict sediment, which has large ratios of light-to-heavy REEs (∑Ce/∑Y ratio) and lacks evident negative Ce anomaly; cerium enrichment is possibly related to manganese transfer under oxidizing conditions in early diagenesis.

  3. Summer sea ice characteristics of the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    During August 1999, we investigated sea ice characteristics; its distribution, surface feature, thickness, ice floe movement, and the temperature field around inter-borders of air/ice/seawater in the Chukchi Sea. Thirteen ice cores were drilled at 11 floe stations in the area of 72°24′ 77°18′N, 153°34′ 163°28′W and the ice core structure was observed. From field observation, three melting processes of ice were observed; surface layer melting, surface and bottom layers melting, and all of ice melting. The observation of temperature fields around sea ice floes showed that the bottom melting under the ice floes were important process. As ice floes and open water areas were alternately distributed in summer Arctic Ocean; the water under ice was colder than the open water by 0.4 2.8℃. The sun radiation heated seawater in open sea areas so that the warmer water went to the bottom when the ice floes move to those areas. This causes ice melting to start at the bottom of the ice floes. This process can balance effectively the temperature fluctuating in the sea in summer. From the crystalline structure of sea ice observed from the cores, it was concluded that the ice was composed of ice crystals and brine-ice films. During the sea ice melting, the brine-ice films between ice crystals melted firstly; then the ice crystals were encircled by brine films; the sea ice became the mixture of ice and liquid brine. At the end of melting, the ice crystals would be separated each other, the bond between ice crystals weakens and this leads to the collapse of the ice sheet.

  4. Late summer zoogeography of the northern Bering and Chukchi seas

    Science.gov (United States)

    Sigler, Michael F.; Mueter, Franz J.; Bluhm, Bodil A.; Busby, Morgan S.; Cokelet, Edward D.; Danielson, Seth L.; Robertis, Alex De; Eisner, Lisa B.; Farley, Edward V.; Iken, Katrin; Kuletz, Kathy J.; Lauth, Robert R.; Logerwell, Elizabeth A.; Pinchuk, Alexei I.

    2017-01-01

    Ocean currents, water masses, and seasonal sea ice formation contribute to determining relationships among the biota of the Bering and Chukchi seas. The Bering Sea communicates with the Chukchi Sea via northward advection of water, nutrients, organic matter, and plankton through Bering Strait. We used data from concurrent surveys of zooplankton, pelagic fishes and jellyfish, epibenthic fishes and invertebrates, and seabirds to identify faunal distribution patterns and environmental factors that are related to these faunal distributions within the US portions of the Chukchi Sea shelf and Bering Sea shelf north of Nunivak Island. Regional differences in late summer (August-September) distributions of biota largely reflected the underlying hydrography. Depth, temperature, salinity, stratification, and chlorophyll a, but less so sediment-related or nutrient-related factors, were related to the distributions of the assemblages (zooplankton: depth, salinity, stratification; pelagic fishes and jellyfish: depth, stratification, chlorophyll a; epibenthic fishes and invertebrates: depth, temperature, salinity; seabirds: temperature, salinity, stratification). These six environmental factors that most influenced distributions of zooplankton, pelagic fishes/jellyfish, epibenthic fishes and invertebrate, and seabird assemblages likely can be simplified to three factors reflecting bottom depth, water mass, and their stratification and productivity (which are tightly linked in the study region). The assemblages were principally structured from nearshore to offshore and from south to north. The nearshore to offshore contrast usually was stronger in the south, where the enormous discharge of the Yukon River is more apparent and extends farther offshore, influencing zooplankton, pelagic fish/jellyfish, and seabird assemblages. Some assemblages overlapped spatially (e.g., seabird and zooplankton), indicating shared influential environmental factors or trophic linkages among

  5. Recurring Spring Leads and Landfast Ice in the Beaufort and Chukchi Seas, 1993-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the Beaufort and Chukchi Seas, the most significant sea ice anomalies have occurred in the summer ice extent (Eicken et al. 2006). In addition, there has been a...

  6. Walrus used and available resource units for northeast Chukchi Sea, 2008-2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Sea ice loss represents a stressor to the Pacific walrus (Odobenus rosmarus divergens), which feeds on benthic macroinvertebrates in the Bering and Chukchi seas....

  7. Aerial Surveys of Endangered Whales in the Beaufort Sea, Chukchi Sea, and Northern Bering Sea.

    Science.gov (United States)

    1981-06-01

    16 Surveys of St Lawrence Island Nome to Point Barrow . . . 16 I Surveys of Barrow Area . . 18 Point Barrow to Deadhorse . . . 20 Surveys from...lease area, the Norton Basin - St . Lawrence Island area, the Hope Basin, and coastal portions of the Chukchi Sea. DESIGN The areas of study are listed...Bowhead Whale 314 857 Balaena mysticetus Beluga Whale** 284 3404 Delphinapterus leucas Gray Whale 2 6 Eschrichtius robustus Ring Seal 250 765 Phoca

  8. Epibenthic community variability in the northeastern Chukchi Sea

    Science.gov (United States)

    Ravelo, Alexandra M.; Konar, Brenda; Trefry, John H.; Grebmeier, Jacqueline M.

    2014-04-01

    Epibenthic organisms can occur in large numbers and high biomass on the continental shelf of the northeastern Chukchi Sea. From an ecosystem perspective, epibenthic organisms are important in recycling and redistributing organic matter deposited from the pelagic zone, and they also are key members of the local food web. Data for biological (epibenthic species composition, abundance, and biomass) and environmental (bottom water temperature, salinity, dissolved oxygen and pH, sediment grain size, sediment organic matter and sediment chlorophyll content, latitude, longitude, and water depth) variables were collected at 53 stations in the northeastern Chukchi Sea during the summers of 2009-2010 to characterize the epibenthos and provide a benchmark for potential future changes due to possible anthropogenic disturbances. Community biomass, abundance, species composition and taxa richness varied in patches throughout the study area, but were generally dominated by crustaceans and echinoderms. These two groups had an inverse relationship in the distribution of their dominance. Communities dominated by crustaceans had significantly higher Simpson's dominance and Pielou's evenness values compared to echinoderm-dominated communities. Correlation coefficients for six environmental variables (longitude, bottom water temperature, water depth, bottom water dissolved oxygen, sediment grain size 2 phi and total organic carbon) with epifaunal abundance and biomass were moderate (0.42 for abundance and 0.51 for biomass at a significance level of 0.1%). However, assemblages within the study area followed a distinct spatial distribution pattern that matched the path of important water masses in the region.

  9. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions.

    Directory of Open Access Journals (Sweden)

    Karyn D Rode

    Full Text Available Recent observations suggest that polar bears (Ursus maritimus are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986-1995 and 2008-2013 when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia, highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions.

  10. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions

    Science.gov (United States)

    Rode, Karyn D.; Wilson, Ryan R.; Regehr, Eric V.; St. Martin, Michelle; Douglas, David C.; Olson, Jay

    2015-01-01

    Recent observations suggest that polar bears (Ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986–1995 and 2008–2013) when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia), highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions. PMID:26580809

  11. Latitudinal distribution of iodine in sediments in the Chukchi Sea and the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    GAO; Aiguo; (高爱国); LIU; Yanguang; (刘焱光); ZHANG; Daojian; (张道建); SUN; Haiqing; (孙海清)

    2003-01-01

    Iodine is an important trace element associated closely with human being, and it will influence human's normal growth if lacking it. Meanwhile, iodine is an important catalyzer, and is important in atmospheric chemistry study. In nature, iodine is rich mainly in marine organism and sediment, and marine sediment has the largest storage of iodine. The analysis results of sediment samples obtained by the First Chinese National Arctic Research Expedition indicate that iodine contents in sediments in the Chukchi Sea and the Bering Sea are 98.1(10-6 and 73.8(10-6, respectively, which are higher than those in sediments of Chinese marginal seas and the southern Pacific Ocean, and show the trend of increase from low latitude to high latitude. This paper proposes a pattern of iodine latitudinal distribution on the basis of the distribution characteristic of iodine and its enrichment mechanism in sediments of the Chukchi Sea and the Bering Sea.

  12. PMEL EcoFOCI Chukchi Sea profile data, 2010-2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific Marine Environmental Laboratory (PMEL) Fisheries-Oceanography Cooperative Investigations (FOCI) Chukchi Sea. PMEL EcoFOCI data from a local source.

  13. AFSC/RACE/MACE: Results of 2012 Chukchi Sea Acoustic/Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We conducted acoustic-trawl (AT) surveys of the Alaska northern Bering and Chukchi Seas during ice-free periods with a focus on Arctic cod (Boreogadus saida), a key...

  14. Tectonics of Chukchi Sea Shelf sedimentary basins and its influence on petroleum systems

    Science.gov (United States)

    Agasheva, Mariia; Antonina, Stoupakova; Anna, Suslova; Yury, Karpov

    2016-04-01

    The Chukchi Sea Shelf placed in the East Arctic offshore of Russia between East Siberian Sea Shelf and North Slope Alaska. The Chukchi margin is considered as high petroleum potential play. The major problem is absence of core material from drilling wells in Russian part of Chukchi Shelf, hence strong complex geological and geophysical analyses such as seismic stratigraphy interpretation should be provided. In addition, similarity to North Slope and Beaufort Basins (North Chukchi) and Hope Basin (South Chukchi) allow to infer the resembling sedimentary succession and petroleum systems. The Chukchi Sea Shelf include North and South Chukchi Basins, which are separated by Wrangel-Herald Arch and characterized by different opening time. The North Chukchi basin is formed as a general part of Canada Basin opened in Early Cretaceous. The South Chukchi Basin is characterized by a transtensional origin of the basin, this deformation related to motion on the Kobuk Fault [1]. Because seismic reflections follow chronostratigraphic correlations, it is possible to achieve stratigraphic interpretation. The main seismic horizons were indicated as: PU, JU, LCU, BU, mBU marking each regional unconformities. Reconstruction of main tectonic events of basin is important for building correct geological model. Since there are no drilling wells in the North and South Chukchi basins, source rocks could not be proven. Referring to the North Chukchi basin, source rocks equivalents of Lower Cretaceous Pebble Shale Formation, Lower Jurassic Kingdak shales and Upper Triassic Shublik Formation (North Slope) is possible exhibited [2]. In the South Chukchi, it is possible that Cretaceous source rocks could be mature for hydrocarbon generation. Erosions and uplifts that could effect on hydrocarbon preservation was substantially in Lower Jurassic and Early Cretaceous periods. Most of the structures may be connected with fault and stratigraphy traps. The structure formed at Wrangel-Herald Arch to

  15. Seasonal distribution of short-tailed shearwaters and their prey in the Bering and Chukchi seas

    Science.gov (United States)

    Nishizawa, Bungo; Matsuno, Kohei; Labunski, Elizabeth A.; Kuletz, Kathy J.; Yamaguchi, Atsushi; Watanuki, Yutaka

    2017-01-01

    The short-tailed shearwater (Ardenna tenuirostris) is one of the abundant marine top predators in the Pacific; this seabird spends its non-breeding period in the northern North Pacific during May-October and many visit the southern Chukchi Sea in August-September. We examined potential factors affecting this seasonal pattern of distribution by counting short-tailed shearwaters from boats. Their main prey, krill, was sampled by net tows in the southeastern Bering Sea/Aleutian Islands and in the Bering Strait/southern Chukchi Sea. Short-tailed shearwaters were mainly distributed in the southeastern Bering Sea/Aleutian Islands (60 ± 473 birds km-2) in July 2013, and in the Bering Strait/southern Chukchi Sea (19 ± 91 birds km-2) in September 2012. In the Bering Strait/southern Chukchi Sea, krill size was greater in September 2012 (9.6 ± 5.0 mm in total length) than in July 2013 (1.9 ± 1.2 mm). Within the Bering Strait/southern Chukchi Sea in September 2012, short-tailed shearwaters occurred more frequently in cells (50 × 50 km) where large-sized krill were more abundant. These findings, and information previously collected in other studies, suggest that the seasonal northward movement of short-tailed shearwaters might be associated with the seasonal increase in krill size in the Bering Strait/southern Chukchi Sea. We could not, however, rule out the possibility that large interannual variation in krill abundance might influence the seasonal distribution of shearwaters. This study highlights the importance of krill, which is advected from the Pacific, as an important prey of top predators in the Arctic marine ecosystem.

  16. SPECIES IDENTIFICATION and Other Data from AIRCRAFT From Chukchi Sea from 19890920 to 19891103 (NODC Accession 9000139)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Whale monitoring biological data was collected from Chukchi Sea by Sea World Research Institute, San Diego, CA. The data was collected over three month period...

  17. Chemistry of Aerosols over Chukchi Sea and Bering Sea

    Institute of Scientific and Technical Information of China (English)

    朱赖民; 陈立奇; 杨绪林; 杜俊民; 张远辉

    2004-01-01

    The contents of elements in aerosols sampled during the First Chinese Arctic Research Expedition (CHINARE-1) show great differences from one element to another. Na, K,Ca, Mg, Al, F, and Cl are the major components in the aerosols, whose contents are larger than 30 ng/m3. The chemical elements whose contents vary between 0.1-30 ng/m3 are Br,Sr, Cr, Ni, and Zn. The chemical elements whose contents are close to or slightly higher than 0. 1 ng/m3 are Rb, Ba, Zr, Th, and Pb. The contents of As, Sb, W, Mo, Au, La, Ce, Nd,Sm, Eu, Tb, Yb, Lu, Sc, Co, Hf, Ta, and Cd are less than 0.1 ng/m3. The mass concentration data for the same element, as observed during CHINARE-1, are almost accordant, but much lower than what is observed in the China' s seas or the coasts of China. The enrichment factor and electron microscopic analyses and lead isotope tracing were used to distinguish their sources.Four groups of sources can be classified as follows: anthropogenic: As, Sb, W, F, Mo, Au,Cu, Pb, Cd, V; crustal: La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Fe, Sc, Cr, Co, Ba, Zr, Hf,Ta, Cs, Mn, Th, U; oceanic:Na, K, Ca, and Mg; and mixing: Rb, Sr, Ca, and Mg.

  18. Fish communities across a spectrum of habitats in the western Beaufort Sea and Chukchi Sea

    Science.gov (United States)

    Logerwell, E.; Busby, M.; Carothers, C.; Cotton, S.; Duffy-Anderson, J.; Farley, E.; Goddard, P.; Heintz, R.; Holladay, B.; Horne, J.; Johnson, S.; Lauth, B.; Moulton, L.; Neff, D.; Norcross, B.; Parker-Stetter, S.; Seigle, J.; Sformo, T.

    2015-08-01

    The increased scientific interest in the Arctic due to climate change and potential oil and gas development has resulted in numerous surveys of Arctic marine fish communities since the mid-2000s. Surveys have been conducted in nearly all Arctic marine fish habitats: from lagoons, beaches and across the continental shelf and slope. This provides an opportunity only recently available to study Arctic fish communities across a spectrum of habitats. We examined fish survey data from lagoon, beach, nearshore benthic, shelf pelagic and shelf benthic habitats in the western Beaufort Sea and Chukchi Sea. Specifically, we compare and contrast relative fish abundance and length (a proxy for age) among habitats and seas. We also examined ichthyoplankton presence/absence and abundance of dominant taxa in the shelf habitat. Our synthesis revealed more similarities than differences between the two seas. For example, our results show that the nearshore habitat is utilized by forage fish across age classes, and is also a nursery area for other species. Our results also indicated that some species may be expanding their range to the north, for example, Chinook Salmon. In addition, we documented the presence of commercially important taxa such as Walleye Pollock and flatfishes (Pleuronectidae). Our synthesis of information on relative abundance and age allowed us to propose detailed conceptual models for the life history distribution of key gadids in Arctic food webs: Arctic and Saffron Cod. Finally, we identify research gaps, such as the need for surveys of the surface waters of the Beaufort Sea, surveys of the lagoons of the Chukchi Sea, and winter season surveys in all areas. We recommend field studies on fish life history that sample multiple age classes in multiple habitats throughout the year to confirm, resolve and interpret the patterns in fish habitat use that we observed.

  19. Chemical and benthos data collected from CTD, bottle, and other instruments in the Chukchi Sea in 2009-2010 as part of the Chukchi Sea Offshore Monitoring in Drilling Area - Chemical and Benthos (COMIDA-CAB) project (NODC Accession 0095566)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains physical, chemical, and biological data collected during research cruises for the Chukchi Sea Offshore Monitoring in Drilling Area (Chemical...

  20. Physical, chemical, biological, geophysical, and meteorological data collected in the Arctic Ocean and Chukchi Sea in support of the Chukchi Sea Environmental Studies Program (CSESP) from 2007 to 2014 (NODC Accession 0124308)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set was collected as part of the Chukchi Sea Environmental Studies Program (CSESP), a multi-year, interdisciplinary ecological study focused on areas in...

  1. Marine mammal observations collected using aircraft by ConocoPhillips in the Chukchi Sea, 1989-1991 and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas (NODC Accession 0120533)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vessel- and aircraft-based marine mammal surveys in the Chukchi Sea collected from 1989 to 1991. The aerial marine mammal surveys were...

  2. SBI AWS02-I CTD Data collected from the Polar Star in the Beaufort and Chukchi Seas (NODC Accession 0001290)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The field phase of the Shelf-Basin Interactions Experiment (SBI) began in 2002 with a series of three cruises to the Chukchi and Beaufort Seas. SBI is a...

  3. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service 2012 Chukchi Sea Bottom Trawl Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the 2012 NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the Chukchi Sea. 71 survey stations were...

  4. AFSC/NMML: Passive acoustic sonobuoy recordings from Bering, Chukchi, and Beaufort Seas in Alaska, 2007-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine spatio-temporal...

  5. Sound velocity and related properties of seafloor sediments in the Bering Sea and Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    MENG Xiangmei; LI Guanbao; HAN Guozhong; KAN Guangming

    2015-01-01

    The Bering Sea shelf and Chukchi Sea shelf are believed to hold enormous oil and gas reserves which have attracted a lot of geophysical surveys. For the interpretation of acoustic geophysical survey results, sediment sound velocity is one of the main parameters. On seven sediment cores collected from the Bering Sea and Chukchi Sea during the 5th Chinese National Arctic Research Expedition, sound velocity measurements were made at 35, 50, 100, 135, 150, 174, 200, and 250 kHz using eight separate pairs of ultrasonic transducers. The measured sound velocities range from 1 425.1 m/s to 1 606.4 m/s and are dispersive with the degrees of dispersion from 2.2% to 4.0% over a frequency range of 35–250 kHz. After the sound velocity measurements, the measurements of selected geotechnical properties and the Scanning Electron Microscopic observation of microstructure were also made on the sediment cores. The results show that the seafloor sediments are composed of silty sand, sandy silt, coarse silt, clayey silt, sand-silt-clay and silty clay. Aggregate and diatom debris is found in the seafloor sediments. Through comparative analysis of microphotographs and geotechnical properties, it is assumed that the large pore spaces between aggregates and the intraparticulate porosity of diatom debris increase the porosity of the seafloor sediments, and affect other geotechnical properties. The correlation analysis of sound velocity and geotechnical properties shows that the correlation of sound velocity with porosity and wet bulk density is extreme significant, while the correlation of sound velocity with clay content, mean grain size and organic content is not significant. The regression equations between porosity, wet bulk density and sound velocity based on best-fit polynomial are given.

  6. The Holocene Records of Glycerol Dialkyl Glycerol Tetraethers From the Northern Chukchi Sea

    Science.gov (United States)

    Park, Y.; Yamamoto, M.; Nam, S.; Polyak, L. V.

    2013-12-01

    We analyzed glycerol dialkyl glycerol tetraethers (GDGTs) in Cores HOTRAX 05-01 JPC5 and JPC 8, and ARA02B 01-GC in the northern Chukchi Sea. All of the three cores showed a similar changing pattern in GDGT composition during the Holocene. In the beginning of early Holocene, both isoprenoid and branched GDGT concentrations were low, and BIT and CBT were relatively high. The similar composition is found in modern sediments from the western Arctic Ocean north of 75°N, suggesting that the northern Chukchi Sea was covered by perennial sea ice. GDGT concentration increased, and BIT and CBT decreased during the early Holocene and reached the same level as those in modern sediments at 8 ka. TEX86 and CBT/MBT indices showed millennial-scale variation. We interpret that these proxies did not simply indicate temperatures but were affected by the relative contribution of different sediment sources. Millennial-scale variability likely reflected changes in sediment transport in the northern Chukchi Sea.

  7. Habitat selection by two beluga whale populations in the Chukchi and Beaufort seas

    Science.gov (United States)

    Laidre, Kristin L.; Stern, Harry L.; Moore, Sue E.; Suydam, Robert S.; Richard, Pierre R.

    2017-01-01

    There has been extensive sea ice loss in the Chukchi and Beaufort seas where two beluga whale (Delphinapterus leucas) populations occur between July-November. Our goal was to develop population-specific beluga habitat selection models that quantify relative use of sea ice and bathymetric features related to oceanographic processes, which can provide context to the importance of changing sea ice conditions. We established habitat selection models that incorporated daily sea ice measures (sea ice concentration, proximity to ice edge and dense ice) and bathymetric features (slope, depth, proximity to the continental slope, Barrow Canyon, and shore) to establish quantitative estimates of habitat use for the Eastern Chukchi Sea (‘Chukchi’) and Eastern Beaufort Sea (‘Beaufort’) populations. We applied ‘used v. available’ resource selection functions to locations of 65 whales tagged from 1993–2012, revealing large variations in seasonal habitat selection that were distinct between sex and population groups. Chukchi whales of both sexes were predicted to use areas in close proximity to Barrow Canyon (typically <200 km) as well as the continental slope in summer, although deeper water and denser ice were stronger predictors for males than females. Habitat selection differed more between sexes for Beaufort belugas. Beaufort males selected higher ice concentrations (≥40%) than females (0–40%) in July-August. Proximity to shore (<200 km) strongly predicted summer habitat of Beaufort females, while distance to the ice edge was important for male habitat selection, especially during westward migration in September. Overall, our results indicate that sea ice variables were rarely the primary drivers of beluga summer-fall habitat selection. While diminished sea ice may indirectly affect belugas through changes in the ecosystem, associations with bathymetric features that affect prey availability seemed key to habitat selection during summer and fall. These

  8. Diet compositions and trophic guild structure of the eastern Chukchi Sea demersal fish community

    Science.gov (United States)

    Whitehouse, George A.; Buckley, Troy W.; Danielson, Seth L.

    2017-01-01

    Fishes are an important link in Arctic marine food webs, connecting production of lower trophic levels to apex predators. We analyzed 1773 stomach samples from 39 fish species collected during a bottom trawl survey of the eastern Chukchi Sea in the summer of 2012. We used hierarchical cluster analysis of diet dissimilarities on 21 of the most well sampled species to identify four distinct trophic guilds: gammarid amphipod consumers, benthic invertebrate generalists, fish and shrimp consumers, and zooplankton consumers. The trophic guilds reflect dominant prey types in predator diets. We used constrained analysis of principal coordinates (CAP) to determine if variation within the composite guild diets could be explained by a suite of non-diet variables. All CAP models explained a significant proportion of the variance in the diet matrices, ranging from 7% to 25% of the total variation. Explanatory variables tested included latitude, longitude, predator length, depth, and water mass. These results indicate a trophic guild structure is present amongst the demersal fish community during summer in the eastern Chukchi Sea. Regular monitoring of the food habits of the demersal fish community will be required to improve our understanding of the spatial, temporal, and interannual variation in diet composition, and to improve our ability to identify and predict the impacts of climate change and commercial development on the structure and functioning of the Chukchi Sea ecosystem.

  9. Oxygen isotopic composition and its application to the study of tracing oceanographical process in Bering Sea and Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    尹明端; 曾宪章; 曾文义; 吴世炎; 施纯坦

    2002-01-01

    In this paper, the 18O distribution of surface water from the central sea areas of the Bering Sea and the Chukchi Sea was studied. The δ18O value of surface water from the Bering Sea is averagely -0.5‰; the δ18O contents of the Chukchi Sea are distributionally lower in northeast and higher in southwest; the δ18O value at the margin of Canadian Basin is -2.8‰, and averagely -0.8‰ in the southern area of the Chukchi Sea. The δ18O vertical distribution in some deep water stations from the Chukchi Sea and the Bering Sea is also studied. In the southern margin of Canadian Basin, the δ18O value is -2‰ -3‰ for surface layer and rises to 0 at 100 m depth layer. In the Bering Sea, the δ18O is about -0.5‰ for surface layer and increases to 0 at the depth of 300 m. The NO tracer can reflect obviously three water masses vertically distributed in the central Bering Sea: the upper Bering water mass, the middle Bering water mass and the deep Pacific water mass. The distributive ranges of NO and temperature for the various water masses are T780 μmol/dm3 and T≥7℃, NO>650 μmol/dm3 for upper Bering water mass, T<4℃, 550sea bottom. Its isotopic characteristics are the same as the Atlantic water, showing that the sea water comes from the north Atlantic. The freshwater end-member of the Chukchi Sea in the survey period is also explored.

  10. Ontogenetic, spatial and temporal variation in trophic level and diet of Chukchi Sea fishes

    Science.gov (United States)

    Marsh, Jennifer M.; Mueter, Franz J.; Iken, Katrin; Danielson, Seth

    2017-01-01

    Climate warming and increasing development are expected to alter the ecosystem of the Chukchi Sea, including its fish communities. As a component of the Arctic Ecosystem Integrated Survey, we assessed the ontogenetic, spatial and temporal variability of the trophic level and diet of key fish species in the Chukchi Sea using N and C stable isotopes. During August and September of 2012 and 2013, 16 common fish species and two primary, invertebrate consumers were collected from surface, midwater and bottom trawls within the eastern Chukchi Sea. Linear mixed-effects models were used to detect possible variation in the relationship between body length and either δ13C or δ15N values among water masses and years for 13 fish species with an emphasis on Arctic cod (Boreogadus saida). We also examined the fish community isotopic niche space, trophic redundancy, and trophic separation within each water mass as measures of resiliency of the fish food web. Ontogenetic shifts in trophic level and diet were observed for most species and these changes tended to vary by water mass. As they increased in length, most fish species relied more on benthic prey with the exception of three forage fish species (walleye pollock, Gadus chalcogrammus, capelin, Mallotus villosus, and Pacific sandlance, Ammodytes hexapterus). Species that exhibited interannual differences in diet and trophic level were feeding at lower trophic levels and consumed a more pelagic diet in 2012 when zooplankton densities were higher. Fish communities occupied different isotopic niche spaces depending on water mass association. In more northerly Arctic waters, the fish community occupied the smallest isotopic niche space and relied heavily on a limited range of intermediate δ13C prey, whereas in warmer, nutrient-rich Bering Chukchi Summer Water, pelagic prey was important. In the warmest, Pacific-derived coastal water, fish consumed both benthic and pelagic prey. Examining how spatial gradients in trophic

  11. Arctic sea ice decline: Projected changes in timing and extent of sea ice in the Bering and Chukchi Seas

    Science.gov (United States)

    Douglas, D.C.

    2010-01-01

    The Arctic region is warming faster than most regions of the world due in part to increasing greenhouse gases and positive feedbacks associated with the loss of snow and ice cover. One consequence has been a rapid decline in Arctic sea ice over the past 3 decades?a decline that is projected to continue by state-of-the-art models. Many stakeholders are therefore interested in how global warming may change the timing and extent of sea ice Arctic-wide, and for specific regions. To inform the public and decision makers of anticipated environmental changes, scientists are striving to better understand how sea ice influences ecosystem structure, local weather, and global climate. Here, projected changes in the Bering and Chukchi Seas are examined because sea ice influences the presence of, or accessibility to, a variety of local resources of commercial and cultural value. In this study, 21st century sea ice conditions in the Bering and Chukchi Seas are based on projections by 18 general circulation models (GCMs) prepared for the fourth reporting period by the Intergovernmental Panel on Climate Change (IPCC) in 2007. Sea ice projections are analyzed for each of two IPCC greenhouse gas forcing scenarios: the A1B `business as usual? scenario and the A2 scenario that is somewhat more aggressive in its CO2 emissions during the second half of the century. A large spread of uncertainty among projections by all 18 models was constrained by creating model subsets that excluded GCMs that poorly simulated the 1979-2008 satellite record of ice extent and seasonality. At the end of the 21st century (2090-2099), median sea ice projections among all combinations of model ensemble and forcing scenario were qualitatively similar. June is projected to experience the least amount of sea ice loss among all months. For the Chukchi Sea, projections show extensive ice melt during July and ice-free conditions during August, September, and October by the end of the century, with high agreement

  12. Quantifying the Bering Strait Oceanic Fluxes and their Impacts on Sea-Ice and Water Properties in the Chukchi and Beaufort Seas and Western Arctic Ocean for 2013-2014

    Science.gov (United States)

    2014-09-30

    Impacts on Sea- Ice and Water Properties in the Chukchi and Beaufort Seas and Western Arctic Ocean for 2013-2014 Rebecca Woodgate Polar Science...from the Pacific, are critical to the water properties of the Chukchi Sea, act as a trigger of sea- ice melt in the Chukchi, provide a subsurface...source of heat to the Arctic in winter (with possible impacts on sea- ice ), and are a major component of freshwater input to the Arctic (Figures 1 and 2

  13. Grain size analysis data collected by sediment corer and sediment grabber casts in the Chukchi sea from 1986-08-29 to 1987-10-07 (NODC Accession 9500158)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Grain size analysis data were collected by using sediment corer and sediment graber casts in the Chukchi Sea and NW Coast of Alaska by the Chukchi Sea. Data were...

  14. Marine mammal acoustic detections in the northeastern Chukchi Sea, September 2007-July 2011

    Science.gov (United States)

    Hannay, David E.; Delarue, Julien; Mouy, Xavier; Martin, Bruce S.; Leary, Del; Oswald, Julie N.; Vallarta, Jonathan

    2013-09-01

    Several cetacean and pinniped species use the northeastern Chukchi Sea as seasonal or year-round habitat. This area has experienced pronounced reduction in the extent of summer sea ice over the last decade, as well as increased anthropogenic activity, particularly in the form of oil and gas exploration. The effects of these changes on marine mammal species are presently unknown. Autonomous passive acoustic recorders were deployed over a wide area of the northeastern Chukchi Sea off the coast of Alaska from Cape Lisburne to Barrow, at distances from 8 km to 200 km from shore: up to 44 each summer and up to 8 each winter. Acoustic data were acquired at 16 kHz continuously during summer and on a duty cycle of 40 or 48 min within each 4-h period during winter. Recordings were analyzed manually and using automated detection and classification systems to identify calls. Bowhead (Balaena mysticetus) and beluga (Delphinapterus leucas) whale calls were detected primarily from April through June and from September to December during their migrations between the Bering and Beaufort seas. Summer detections were rare and usually concentrated off Wainwright and Barrow, Alaska. Gray (Eschrichtius robustus) whale calls were detected between July and October, their occurrence decreasing with increasing distance from shore. Fin (Balaenoptera physalus), killer (Orcinus orca), minke (Balaenoptera acutorostrata), and humpback (Megaptera novaeangliae) whales were detected sporadically in summer and early fall. Walrus (Odobenus rosmarus) was the most commonly detected species between June and October, primarily occupying the southern edge of Hanna Shoal and haul-outs near coastal recording stations off Wainwright and Point Lay. Ringed (Pusa hispida) and bearded (Erignathus barbatus) seals occur year-round in the Chukchi Sea. Ringed seal acoustic detections occurred throughout the year but detection numbers were low, likely due to low vocalization rates. Bearded seal acoustic detections

  15. Observations and modeling of the ice-ocean conditions in the coastal Chukchi and Beaufort Seas

    Institute of Scientific and Technical Information of China (English)

    JIN Meibing; WANG Jia; MIZOBATA Kohei; HU Haoguo; SHIMADA Koji

    2008-01-01

    The Chukchi and Beaufort Seas include several important hydrological features: inflow of the Pacific water, Alaska coast current (ACC), the seasonal to perennial sea ice cover, and landfast ice along the Alaskan coast. The dynamics of this coupled ice-ocean sys-tem is important for both regional scale oceanography and large-scale global climate change research. A number of moorings were de-ployed in the area by JAMSTEC since 1992, and the data revealed highly variable characteristics of the hydrological environment. A re-gional high-resolution coupled ice-ocean model of the Chukchi and Beaufort Seas was established to simulate the ice-ocean environment and unique seasonal landfast ice in the coastal Beaufort Sea. The model results reproduced the Beaufort gyre and the ACC. The depth-averaged annual mean ocean currents along the Beaufort Sea coast and shelf break compared well with data from four moored ADCPs, but the simulated velocity had smaller standard deviations, which indicate small-scale eddies were frequent in the region. The model re-suits captured the seasonal variations of sea ice area as compared with remote sensing data, and the simulated sea ice velocity showed an almost stationary area along the Beaufort Sea coast that was similar to the observed landfast ice extent. It is the combined effects of the weak oceanic current near the coast, a prevailing wind with an onshore component, the opposite direction of the ocean current, and the blocking by the coastline that make the Beaufort Sea coastal areas prone to the formation of landfast ice.

  16. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering and Chukchi seas

    Science.gov (United States)

    Sasaki, Hiroko; Matsuno, Kohei; Fujiwara, Amane; Onuka, Misaki; Yamaguchi, Atsushi; Ueno, Hiromichi; Watanuki, Yutaka; Kikuchi, Takashi

    2016-08-01

    The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed habitat models explaining the spatial patterns of large and small Arctic and Pacific copepods separately. Copepods were sampled using NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle component analysis scores, satellite-derived timing of sea ice retreat, bottom depth and chlorophyll a concentration were integrated into generalized additive models as explanatory variables. The adequate models for all copepods exhibited clear continuous relationships between the abundance of copepods and the indexed water masses. Large Arctic copepods were abundant at stations where the bottom layer was saline; however they were scarce at stations where warm fresh water formed the upper layer. Small Arctic copepods were abundant at stations where the upper layer was warm and saline and the bottom layer was cold and highly saline. In contrast, Pacific copepods were abundant at stations where the Pacific-origin water mass was predominant (i.e. a warm, saline upper layer and saline and a highly saline bottom layer). All copepod groups showed a positive relationship with early sea ice retreat. Early sea ice retreat has been reported to initiate spring blooms in open water, allowing copepods to utilize more food while maintaining their high activity in warm water without sea ice and cold water. This finding indicates that early sea ice retreat has positive effects on the abundance of all copepod groups in the northern Bering and Chukchi seas, suggesting a change from a pelagic-benthic-type ecosystem to a pelagic-pelagic type.

  17. An Oceanographic and Climatological Atlas of the Chukchi Sea

    Science.gov (United States)

    1990-02-01

    ZONES....................................... 303 FREEZEUP /BREAKUP DATES.................................... 304-310 5. REFERENCES...42 Average Date of Freezeup ............................ 304 I Figure 43 Median Date of Freezeup ............................. 305 Figure 44 Average...except the southern floor are common in this shear zone since these Bering Sea. FREEZEUP /BREAKUP DATES Building on the earlier work of LaBelle et al

  18. Abundance of general aerobic heterotrophic bacteria in the Bering Sea and Chukchi Sea and their adaptation to temperature

    Institute of Scientific and Technical Information of China (English)

    陈皓文; 高爱国; 孙海青; 矫玉田

    2004-01-01

    The abundance of general aerobic heterotrophic bacteria(GAB) from the water and sediment in the Bering Sea and the Chukchi Sea was determined by using petri dish cultivation and counting method. The abundance of GAB among the different sea areas, sampling sites, layers of sediments surveyed and adaptability to differential temperatures was studied. The result obtained showed that: the occurrence percentage of GAB in the surface water was higher than that in sediment, but the abundance was only 0.17% of sediment. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage, abundance and its variation of GAB in the Bering Sea were higher than that in the Chukchi Sea respectively. The average value of the abundance of GAB in sediment showed a trend: roughly higher in the lower latitudinal area than higher latitude. The results from temperature test mean that: the majority of bacteria tested were cold -adapted ones, minority might be mesophilic bacteria. The results indicated that, Arctic ocean bacteria had a stronger adaptability to environmental temperature.

  19. The Hydromedusae and its distribution in Chukchi Sea and adjacent southern edge waters of Canada Basin, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    张金标; 林茂

    2001-01-01

    The present paper is based on materials collected in Chukchi Sea and adjacent southern edge waters of Canada Basin, Arctic Ocean during the period from July to August 1999 on the icebreaker, the R/V “Xuelong”, by the Chinese First Arctic Scientific Expedition. Totally, 8 species of pelagic Hydromedusae were identified, of which 4 species belonged to Anthomedusae, 2 species to Leptomedusae, 1 species to Trachymedusae and 1 species to Narcomedusae, the Neoturris breviconis is recorded for the first time in Chukchi Sea. Their principal morphological characteristics are described and illustrated. The 8 species of Hydromedusae occurring in the Chukchi Sea were all cold water species, of which 6 species belong to neritic species and 2 species to ocean species. According to the geographic distribution of species, they may be divided into three groups: Arctic species, Arctic-boreal species and Boreal-temperate species. From the view-point of zoogeography, species from these waters belong to the Arctic fauna.The abundance of Hydromedusae in Chukchi Sea was generally low, with a mean value of 108 ind.*10-2*m-3. Rathkea octopunctata and Aglantha digitale were dominant species. From the view-point of vertical distribution Aglantha digitale is inhabiting in the depth of 0 300 m and with the maximum in the depth of 50 m to 100 m.

  20. 76 FR 30956 - Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193

    Science.gov (United States)

    2011-05-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193 AGENCY: Bureau of Ocean Energy...

  1. The substance composition of sterols in the sediments from the Chukchi Sea, the Bering Sea and global climatic significance

    Institute of Scientific and Technical Information of China (English)

    Lu Bing; Hu Chuanyu; Pan Jianming; Xue Bin; YaoMei

    2006-01-01

    The compounds of sterols such as C27 、C28 、C29 and C3o are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5 ,22 as well as 22-,24-. The compound of sterols such as C27、C28、C29 are recorded from B2-9core of the Bering Sea. The double bond position is located at 5-, 5, 22 as well as 22. The composition characteristics of sterols indicate that the substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results are also suggest that the record of abnormal sterols from the surface sediments (2 -0 cm)in the Chukchi Sea and the Bering Sea represent the period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments, which indicates the eco- environmental change responding to climatic effect of circumjacent.

  2. Biodiversity and community structural characteristics of macrobenthos in the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Jianjun; LIN Heshan; HE Xuebao; LIN Junhui; HUANG Yaqin; LI Rongguan; ZHENG Chengxing; ZHENG Fengwu; JIANG Jinxiang

    2014-01-01

    Field sampling of the macrobenthos from 23 stations in the Chukchi Sea was conducted during the 4th CHI-NARE (Chinese National Arctic Research Expeditions, July-August, 2010). We identified a total of 140 species of macrozoobenthos belonging to nine phyla, which were dominated by polychaetes (66), crustaceans (30), and mollusks (25), followed by echinoderms (9) and others (ten others, including four cnidarians, one oli-gochaete, one sipuncula, one priapulida, two bryozoans, and one urochordata). The dominant species were Aphelochaeta pacifica, Heteromastus filiformis, Nephtys ciliata, Nephtys caeca, Scoletoma fragilis, Golfingia margaritacea, Nuculana pernula, Macoma calcarea, Ennucula tenuis, Macoma inquinata, Musculus discors, Echinarachnius parma, and Ophiura sarsii, so there were more cold-eurythermal boreal immigrants than truly Arctic species (endemics). The average density and biomass (mean ± SD across all stations) of the total macrozoobenthos were (916 ± 907) ind/m2 and (902.9 ± 1 227.7) g/m2 (wet weight), respectively. Relatively high density and biomass were observed in the samples from the northeastern and southern Chukchi Sea. The spatial variation of benthic communities in the study sea area was relatively large;this spatial heteroge-neity has led to high diversity and a patchy distribution pattern in the community structure. Compared to the 1st CHINARE ( July-August, 1999), this investigation revealed different degrees of decreases in the aver-age taxa numbers and the average density, abundance, and biodiversity in the area over the recent decade, which might be associated with global warming, human activities, and sea ice variations.

  3. Simulation of phytoplankton distribution and variation in the Bering-Chukchi Sea using a 3-D physical-biological model

    Science.gov (United States)

    Hu, Haoguo; Wang, Jia; Liu, Hui; Goes, Joaquim

    2016-06-01

    A three-dimensional physical-biological model has been used to simulate seasonal phytoplankton variations in the Bering and Chukchi Seas with a focus on understanding the physical and biogeochemical mechanisms involved in the formation of the Bering Sea Green Belt (GB) and the Subsurface Chlorophyll Maxima (SCM). Model results suggest that the horizontal distribution of the GB is controlled by a combination of light, temperature, and nutrients. Model results indicated that the SCM, frequently seen below the thermocline, exists because of a rich supply of nutrients and sufficient light. The seasonal onset of phytoplankton blooms is controlled by different factors at different locations in the Bering-Chukchi Sea. In the off-shelf central region of the Bering Sea, phytoplankton blooms are regulated by available light. On the Bering Sea shelf, sea ice through its influence on light and temperature plays a key role in the formation of blooms, whereas in the Chukchi Sea, bloom formation is largely controlled by ambient seawater temperatures. A numerical experiment conducted as part of this study revealed that plankton sinking is important for simulating the vertical distribution of phytoplankton and the seasonal formation of the SCM. An additional numerical experiment revealed that sea ice algae account for 14.3-36.9% of total phytoplankton production during the melting season, and it cannot be ignored when evaluating primary productivity in the Arctic Ocean.

  4. Wind-driven interannual variability of sea ice algal production over the western Arctic Chukchi Borderland

    Directory of Open Access Journals (Sweden)

    E. Watanabe

    2015-05-01

    Full Text Available Seasonal and interannual variability in sinking flux of biogenic particles was reported by the multi-year bottom-tethered sediment trap measurements in the Northwind Abyssal Plain (Station NAP: 75° N, 162° W, 1975 m water depth of the western Arctic Chukchi Borderland. Whereas the trapped particle flux had an obvious peak with the dominance of sea ice-related diatom valve in August 2011, the observed particle flux was considerably suppressed throughout the summer season in 2012. In the present study, response of ice algal production and biomass to wind-driven changes in physical environments was addressed using a pan-Arctic sea ice–ocean modeling approach. Sea ice ecosystem with ice algae was newly incorporated into the lower-trophic marine ecosystem model, which was previously coupled with a high-resolution (i.e., horizontal grid size of 5 km ocean general circulation model. Seasonal experiments covering two year-long mooring periods indicated that primary productivity of ice algae around the Chukchi Borderland depended on basin-scale wind pattern through various processes. Easterly wind in the southern part of distinct Beaufort High supplied high abundance of nutrient for euphotic zones of the NAP region via both surface Ekman transport of Chukchi shelf water and vertical turbulent mixing with underlying nutricline water as in 2011. In contrast, northwesterly wind flowing in the northern part of extended Siberian High transported oligotrophic water within the Beaufort Gyre circulation toward the NAP region as in 2012. The modeled ice algal biomass during the summer season certainly reflected the differences in nutrient distribution. The sinking flux of Particulate Organic Nitrogen (PON was comparable with the time series obtained from the sediment trap data in summer 2011. On the other hand, lateral advection of shelf-origin ice algal patch during a great cyclone event might have caused a model bias on the PON flux in 2012. The extension

  5. Current meter components and other data from FIXED PLATFORMS from the Chukchi Sea from 27 August 1990 to 05 October 1991 (NODC Accession 9300039)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter components data were collected from FIXED PLATFORMS in the Chukchi Sea from 27 August 1990 to 05 October 1991. Data were collected by the Pacific...

  6. SBI AWS02-I Bottle and Nutrient Data collected from the Polar Star in the Beaufort and Chukchi Seas (NODC Accession 0001288)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The field phase of the Shelf-Basin Interactions Experiment (SBI) began in 2002 with a series of three cruises to the Chukchi and Beaufort Seas. SBI is a...

  7. Vertical characteristics of ozone variation over the Arctic Chukchi Sea region in 1999

    Institute of Scientific and Technical Information of China (English)

    周立波; 刘宇; 邹捍

    2002-01-01

    In 1999 summer, Chinese Arctic Research Expedition operated the Chukchi Sea. On Chinese icebreaker Xuelong, we made many high-resolution ozonesonds measurements. During the period from August 18 to 24, a synoptic scale observation was taken at 75°N, 160°W. Using the above data, together with TOMS total ozone and NCEP circulation data, we showed that atmospheric ozone amount experienced a high-low-high variation, with low-high-low tropopause altitude. Correlation analysis showed a close relation between the total ozone and ozone below 13 km, while the variation of the maximum concentration at about 20 km didn't show any relation to the column ozone. In 500 hPa height maps, there was also the weak-strong-weak southwesterly pattern. Therefore we suggested that the synoptic system might be responsible to a low ozone advection during this ozone variation.

  8. Application of long-chain aikenones and U37k values for paleotemperature estimation in the Arctic Chukchi Sea- Bering Sea area

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    -Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is pre dominate in the long-chain alkenones from the Chukchi and Bering Sea sediments. The abundance of C37to C39 unsaturated alkenones changes in an order of C37 >C38 >C39. Based on ∑37/∑38 ratio, the de tected organism precursors of the long-chain alkenones are mainly coccolithophrid (Emiliania huxleyi).By the calibration relationship between U3k7 and U37k indices, the sea surface paleotemperature in these seas is estimated. The estimated values of U37k vary from 4.147℃ to 5. 706℃, with a mean value of 5.092℃.

  9. The composition and origination of particles from surface water in the Chukchi Sea, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    YU Xiaoguo; LEI Jijiang; YAO Xuying; ZHU Jihao; JIN Xiaobing

    2014-01-01

    Suspended particle samples were collected at 11 stations on the shelf and slope regions of the Chukchi Sea and the central Arctic Ocean during the fifth Chinese National Arctic Research Expedition (summer 2012). The particle concentration, total organic carbon (TOC), total nitrogen (TN) and the isotopic composition of the samples were analyzed. The suspended particle concentration varied between 0.56 and 4.01 mg.L-1;the samples collected from the sea ice margin have higher concentrations. The organic matter content is higher in the shelf area (TOC:9.78%-20.24%;TN:0.91%-2.31%), and exhibits heavier isotopic compositions (δ13C: -23.29‰ to -26.33‰ PDB;δ15N: 6.14‰-7.78‰), indicating that the organic matter is mostly marine in origin with some terrigenous input. In the slope and the central Arctic Ocean, the organic matter content is lower (TOC:8.06%-8.96%;TN:0.46%-0.72%), except for one sample (SR15), and has lighter isotopic compositions (δ13C:-26.93‰to-27.78‰PDB;δ15N:4.13‰-4.84‰). This indicates that the organic matter is mostly terrestrially-derived in these regions. The extremely high amount of terrigenous organic matter (TOC:27.94%;TN:1.16%;δ13C:-27.43‰PDB;δ15N:3.81‰) implies that it was carried by transpolar currents from the East Siberian Sea. Material, including sea ice algae, carried by sea ice are the primary source for particles in the sea ice margins. Sea ice melting released a substantial amount of biomass into the shelf, but a large amount of detrital and clay minerals in the slope and the central Arctic Ocean.

  10. Distribution of molluscan remains in the sediment of the Chukchi Sea and its vicinity, the Arctic

    Institute of Scientific and Technical Information of China (English)

    Gao Aiguo; Xu Fengshan; Sun Haiqing; Li Lon

    2003-01-01

    The result of an analysis of mollusca remains collected from the Chukchi Sea, Beaufort Sea and Bering Sea in the First Chinese National Arctic Research Expedition, from July to September,1999 is presented. Seventeen species of mollusca have been identified, which belong to two classes: Bivalvia and Gastropoda. The compositions of the mollusca are very simple. According to the distribution pattern two groups may be distinguished among molluscan species. The Pan-Arctic and circumboreal group comprises Nuculana pernula, N. radiata, Nucula bellotii, Astarte montagui, Seripes groenlandicus, Macoma calcarea, M. moesta alaskana, Liocyma fluctuosa, Mya pseudoarenaria and Turritella polaris. Three species, Cyclocardia crebricos tata, Trichotrois coronata and Argobuccinum oregonense are components of the Pan-Arctic and Pacific boreal group. With regard to feeding habits, detritus feeders dominate. There are 7 species of detritus feeders, i.e. , Nuculana pernula, N. radiata,Nucula bellotii , Macoma calcarea , M. moesta alaskana , Macoma sp. and Trichotropis coronata . Detritus feeders are dominant with regard to the numbers of species as well as to the frequency of occurrence. Macoma calcarea is the most abundant species.

  11. The conservative behavior of dissolved organic carbon in surface waters of the southern Chukchi Sea, Arctic Ocean, during early summer

    Science.gov (United States)

    Tanaka, Kazuki; Takesue, Nobuyuki; Nishioka, Jun; Kondo, Yoshiko; Ooki, Atsushi; Kuma, Kenshi; Hirawake, Toru; Yamashita, Youhei

    2016-01-01

    The spatial distribution of dissolved organic carbon (DOC) concentrations and the optical properties of dissolved organic matter (DOM) determined by ultraviolet-visible absorbance and fluorescence spectroscopy were measured in surface waters of the southern Chukchi Sea, western Arctic Ocean, during the early summer of 2013. Neither the DOC concentration nor the optical parameters of the DOM correlated with salinity. Principal component analysis using the DOM optical parameters clearly separated the DOM sources. A significant linear relationship was evident between the DOC and the principal component score for specific water masses, indicating that a high DOC level was related to a terrigenous source, whereas a low DOC level was related to a marine source. Relationships between the DOC and the principal component scores of the surface waters of the southern Chukchi Sea implied that the major factor controlling the distribution of DOC concentrations was the mixing of plural water masses rather than local production and degradation. PMID:27658444

  12. A coupled ice-ocean ecosystem model for 1-D and 3-D applications in the Bering and Chukchi Seas

    Institute of Scientific and Technical Information of China (English)

    Jin Meibing; Clara Deal; WANG Jia

    2008-01-01

    Primary production in the Bering and Chukchi Seas is strongly influenced by the annual cycle of sea ice. Here pelagic and sea ice algal ecosystems coexist and interact with each other. Ecosystem modeling of sea ice associated phytoplankton blooms has been understudied compared to open water ecosystem model applications.This study introduces a general coupled ice-ocean ecosystem model with equations and parameters for 1-D and 3-D applications that is based on 1-D coupled ice-ocean ecosystem model development in the landfast ice in the Chukchi Sea and marginal ice zone of Bering Sea. The biological model includes both pelagic and sea ice algal habitats with 10 compartments: three phytoplankton (pelagic diatom, flagellates and ice algae: D, F, and Ai), three zooplankton (copepods, large zooplankton, and microzooplankton: ZS, ZL, ZP), three nutrients (nitrate + nitrite, ammonium, silicon:NO3, NH4, Si) and detritus (Det). The coupling of the biological models with physical ocean models is straightforward with just the addition of the advection and diffusion terms to the ecosystem model. The coupling with a multi-category sea ice model requires the same calculation of the sea ice ecosystem model in each ice thickness category and the redistribution between categories caused by both dynamic and thermodynamic forcing as in the physical model. Phytoplankton and ice algal self-shading effect is the sole feedback from the ecosystem model to the physical model.

  13. Distribution, Abundance, Behavior, and Bioacoustics of Endangered Whales in the Alaskan Beaufort and Eastern Chukchi Seas, 1979-86.

    Science.gov (United States)

    1987-07-01

    Habitat Relationships and Behavior 70 d. Calf Sightings and Estimated Recruitment 72 Other Marine Mammals 72 a. Belukha ( Delphinapterus leucas ) 72 b...been seen in the Chukchi Sea only in 3uly. Other Marine Mammals a. Belukha, or White Whale ( Delphinapterus leucas ) There were 109 sightings of 492...physalus) whales in the St . Lawrence river (Macfarlane, 1981); and minke whales (Balaenoptera acutorostrata) off 3apan (Nishiwaki and Sasao, 1977

  14. International importance of the eastern Chukchi Sea as a staging area for migrating king eiders

    Science.gov (United States)

    Oppel, S.; Dickson, D.L.; Powell, A.N.

    2009-01-01

    The evaluation of habitats used by arctic birds on migration is crucial for their conservation. We explored the importance of the eastern Chukchi Sea (ECS) as a staging area for king eiders (Somateria spectabilis) migrating between breeding areas in Siberia and western North America and wintering areas in the Bering Sea. We tracked 190 king eiders with satellite transmitters between 1997 and 2007. In late summer, 74% of satellite-tracked king eiders migrating south staged in the ECS for 13 ?? 13 (SD) days between late June and early November. During spring migration, king eiders staged in the ECS between mid-April and early June for 21 ?? 10 days. All instrumented birds migrating to breeding grounds in western North America (n = 62), and 6 of 11 males migrating to breeding grounds in Siberia, used this area for at least 1 week during spring migration. The importance of this staging area renders it possible that industrial development could adversely affect king eider populations in both Siberia and North America. ?? 2009 US Government.

  15. Outflow of Pacific water from the Chukchi Sea to the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    Robert S Pickart; Greg Stossmeister

    2008-01-01

    Pacific water exits the Chukchi Sea shelf through Barrow Canyon in the east and Herald Canyon in the west, forming an eastward-directed shelfbreak boundary current that flows into the Beaufort Sea. Here we summarize the transformation that the Pacific water undergoes in the two canyons, and describe the characteristics and variability of the resulting shelfbreak jet, using recently collected summertime hydrographic data and a year-long mooring data set. In both canyons the northward-flowing Pacific winter water switches from the western to the eastern flank of the canyon, interacting with the northward-flowing summer water. In Barrow canyon the vorticity structure of the current is altered, while in Herald canyon a new water mass mode is created. In both instances hydraulic effects are believed to be partly responsible for the observed changes. The shelfbreak jet that forms from the canyon outflows has distinct seasonal configurations, from a bottom-intensified flow carrying cold, dense Pacific water in spring, to a surface-intensified current advecting warm, buoyant water in summer. The current also varies significantly on short timescales, from less than a day to a week. In fall and winter much of this mesoscale variability is driven by storm events, whose easterly winds reverse the current and cause upwelling. Different types of eddies arc spawned from the current, which are characterized here using hydrographic and satellite data.

  16. The Floe Size Distribution in the Marginal Ice Zone of the Beaufort and Chukchi Seas

    Science.gov (United States)

    Schweiger, A. J. B.; Stern, H. L., III; Stark, M.; Zhang, J.; Steele, M.; Hwang, P. B.

    2014-12-01

    Several key processes in the Marginal Ice Zone (MIZ) of the Arctic Ocean are related to the size of the ice floes, whose diameters range from meters to tens of kilometers. The floe size distribution (FSD) influences the mechanical properties of the ice cover, air-sea momentum and heat transfer, lateral melting, and light penetration. However, no existing sea-ice/ocean models currently simulate the FSD in the MIZ. Model development depends on observations of the FSD for parameterization, calibration, and validation. To support the development and implementation of the FSD in the Marginal Ice Zone Modeling and Assimilation System (MIZMAS), we have analyzed the FSD in the Beaufort and Chukchi seas using multiple sources of satellite imagery: NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites (250 m pixel size), the USGS Landsat 8 satellite (80 m pixel size), the Canadian Space Agency's synthetic aperture radar (SAR) on RADARSAT (50 meter pixel size), and declassified National Technical Means imagery from the Global Fiducials Library (GFL) of the USGS (1 m pixel size). The procedure for identifying ice floes in the imagery begins with manually delineating cloud-free regions (if necessary). A threshold is then chosen to separate ice from water. Morphological operations and other semi-automated techniques are used to identify individual floes, whose properties are then easily calculated. We use the mean caliper diameter as the measure of floe size. The FSD is adequately described by a power-law in which the exponent characterizes the relative number of large and small floes. Changes in the exponent over time and space reflect changes in physical processes in the MIZ, such as sea-ice deformation, fracturing, and melting. We report results of FSD analysis for the spring and summer of 2013 and 2014, and show how the FSD will be incorporated into the MIZMAS model.

  17. Reconstruction and analysis of the Chukchi Sea circulation in 1990-1991

    Science.gov (United States)

    Panteleev, G.; Nechaev, D. A.; Proshutinsky, A.; Woodgate, R.; Zhang, J.

    2010-08-01

    The Chukchi Sea (CS) circulation reconstructed for September 1990 to October 1991 from sea ice and ocean data is presented and analyzed. The core of the observational data used in this study comprises the records from 12 moorings deployed in 1990 and 1991 in U.S. and Russian waters and two hydrographic surveys conducted in the region in the fall of 1990 and 1991. The observations are processed by a two-step data assimilation procedure involving the Pan-Arctic Ice-Ocean Modeling and Assimilation System (employing a nudging algorithm for sea ice data assimilation) and the Semi-implicit Ocean Model [utilizing a conventional four-dimensional variational (4D-var) assimilation technique]. The reconstructed CS circulation is studied to identify pathways and assess residence times of Pacific water in the region; quantify the balances of volume, freshwater, and heat content; and determine the leading dynamical factors configuring the CS circulation. It is found that in 1990-1991 (high AO index and a cyclonic circulation regime) Pacific water transiting the CS toward the Canada basin followed two major pathways, namely via Herald Canyon (Herald branch of circulation, 0.23 Sv) and between Herald Shoal and Cape Lisburne (central branch of circulation and Alaskan Coastal Current, 0.32 Sv). The annual mean flow through Long Strait was negligible (0.01 Sv). Typical residence time of Pacific water in the region varied between 150 days for waters entering the CS in September and 270 days for waters entering in February/March. Momentum balance analysis reveals that geostrophic balance between barotropic pressure gradient and Coriolis force dominated for most of the year. Baroclinic effects were important for circulation only in the regions with large horizontal salinity gradients associated with the fresh Alaskan and Siberian coastal currents and the Cape Lisburne and Great Siberian polynyas. In the polynyas, the baroclinic effects were due to strong salinification and convection

  18. Isolation and characterization of a marine bacterium producing protease from Chukchi Sea, Arctic

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A Gram negative bacterium Ar/W/b/75°25'N/1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25'N, and longitude 162°25'W in Chukchi sea, Arctic. The strain can grow at the temperature range from 7℃ to 30℃, and grow better at 30(℃. It can not grow at 40℃. Keeping certain salinity concentration in medium is necessary for cell growth. It grows well in medium containing salinity concentration from 0. 5 % to 10 % sodium chloride. Glucose, sucrose and soluble starch can be utilized by the strain, among which glucose is the optimal carbon source. Peptone is the optimal organic nitrogen source for cell growth and protease producing, and ammonium nitrate is the optimal inorganic nitrogen source.About 75.7% of total protease of the strain are extracellular enzyme. Optimal temperature for proteolytic activity is at 40℃. Protease of the strain keeps stable below 40℃, and shows high proteolytic activity within the pH range from 7 to 11.

  19. The distribution and characteristics of suspended particulate matter in the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Weiguo; FANG Jianyong; CHEN Lili; WU Risheng; YU Xingguang

    2014-01-01

    Samples taken from the Chukchi Sea (CS) during the 4th Chinese National Arctic Research Expedition, 2010, were analyzed to determine the content and composition of suspended particulate matter (SPM) to improve our understanding of the distribution, sources and control factors of the SPM there. The results show that the SPM in the water column is highest in the middle and near the bottom in the south and central-north CS, followed by that off the Alaskan coast and in Barrow Canyon. The SPM content is lowest in the central CS. Scanning electron microscope (SEM) analysis shows that the SPM in the south and central-north CS is composed mainly of diatoms, but the dominant species in those two areas are different. The SPM off the Alaskan coast and in Barrow Canyon is composed mainly of terrigenous material with few bio-skeletal clasts. The distribution of temperature and salinity and the correlation between diatom species in SPM indicate that the diatom dominant SPM in the south CS is from the Pacific Ocean via the Bering Strait in summer. The diatom dominant SPM in the central-north CS is also from Pacific water, which reaches the CS in winter. The SPM in the middle and near the bottom of the water column off the Alaskan coast and in Barrow Canyon is from Alaskan coastal water and terrigenous material transported by rivers in Alaska.

  20. Growth dynamics of saffron cod (Eleginus gracilis) and Arctic cod (Boreogadus saida) in the Northern Bering and Chukchi Seas

    Science.gov (United States)

    Helser, Thomas E.; Colman, Jamie R.; Anderl, Delsa M.; Kastelle, Craig R.

    2017-01-01

    Saffron cod (Eleginus gracilis) and Arctic cod (Boreogadus saida) are two circumpolar gadids that serve as critically important species responsible for energy transfer in Arctic food webs of the northern Bering and Chukchi Seas. To understand the potential effects of sea ice loss and warming temperatures on these species' basic life history, information such as growth is needed. Yet to date, limited effort has been dedicated to the study of their growth dynamics. Based on a large sample of otoliths collected in the first comprehensive ecosystem integrated survey in the northern Bering and Chukchi Seas, procedures were developed to reliably estimate age from otolith growth zones and were used to study the growth dynamics of saffron and Arctic cod. Annual growth zone assignment was validated using oxygen isotope signatures in otoliths and otolith morphology analyzed and compared between species. Saffron cod attained larger asymptotic sizes (L∞=363 mm) and achieved their maximum size at a faster rate (K=0.378) than Arctic cod (L∞=209 mm; K=0.312). For both species, regional differences in growth were found (pArctic cod grew to smaller asymptotic size but at faster rates in the more northerly central (L∞=197 mm;K=0.324) and southern Chukchi Sea (L∞=221 mm;K=0.297) when compared to the northern Bering Sea (L∞=266 mm;K=0.171), suggesting a possible cline in growth rates with more northerly latitudes. Comparison of growth to two periods separated by 30 years indicate that both species exhibited a decline in maximum size accompanied by higher instantaneous growth rates in more recent years.

  1. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

    Science.gov (United States)

    Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

    2015-11-01

    The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

  2. Anthropogenic {sup 129}I in the North Pacific, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, H., E-mail: hnagai@chs.nihon-u.ac.jp [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Hasegawa, A. [Graduate School of Integrated Basic Sciences, Nihon University, Tokyo 156-8550 (Japan); Yamagata, T. [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Kumamoto, Y.; Nishino, S. [Japan Agency for Marine-Earth Science and Technology, Kanagawa 237-0061 (Japan); Matsuzaki, H. [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo 113-0032 (Japan)

    2015-10-15

    Most of anthropogenic {sup 129}I in marine environment are due to discharge from the nuclear fuel reprocessing facilities at Sellafield (U.K.) and La Hague (France) for past few decades. The discharge raised {sup 129}I concentration in seawaters in the North Atlantic and Arctic Oceans to more than 10{sup 9} atoms L{sup −1}, which is two orders of magnitude higher than that in other region. Recently, in March 2011, a large quantity of {sup 129}I was released into the western North Pacific due to the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident. To evaluate the influence of these events, we have measured {sup 129}I concentration in seawaters in the northern North Pacific Ocean, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013. The {sup 129}I concentrations were 1.0–1.8 × 10{sup 7} atoms L{sup −1} in the surface waters in the vicinity of 47°N 150°E–130°W North Pacific Ocean, Bering Sea, and Chukchi Sea (<74°N), which are equal to or lower than the {sup 129}I concentration level in surface water in the North Pacific Ocean before the F1NPP accident. The vertical profiles in the North Pacific were almost same as that observed in the western North Pacific before the F1NPP accident. The {sup 129}I distribution in seawater in the North Pacific to the Chukchi Sea revealed no significant increase of {sup 129}I concentration caused by the F1NPP accident. The {sup 129}I concentrations were 13–14 × 10{sup 7} atoms L{sup −1} in surface waters and 80 × 10{sup 7} atoms L{sup −1} at depths of 300 and 800 m in the Arctic Ocean.

  3. Short-term changes in a microplankton community in the Chukchi Sea during autumn: consequences of a strong wind event

    Science.gov (United States)

    Yokoi, Naoya; Matsuno, Kohei; Ichinomiya, Mutsuo; Yamaguchi, Atsushi; Nishino, Shigeto; Onodera, Jonaotaro; Inoue, Jun; Kikuchi, Takashi

    2016-02-01

    Recent studies indicate an increase in atmospheric turbulence in the Chukchi Sea due to the recent drastic sea-ice reduction during summer months. The importance of the effects of this atmospheric turbulence on the marine ecosystem in this region, however, is not fully understood. To evaluate the effects of atmospheric turbulence on the marine ecosystem, high-frequency sampling (daily) from five layers of the microplankton community between 0 and 30 m at a fixed station in the Chukchi Sea from 10 through 25 September 2013 was conducted. During the study period, a strong wind event (SWE) was observed on 18 and 19 September. The abundance of microplankton was 2.6 to 17.6 cells mL-1, with a maximum abundance being reported at 20 m on 22 September, while diatoms were the most dominant taxa throughout the study period. The abundance of diatoms, dinoflagellates and ciliates ranged between 1.6 and 14.1, 0.5 and 2.4 and 0.1 and 2.8 cells mL-1, respectively. Diatoms belonging to 7 genera consisting of 35 species (Cylindrotheca closterium and Leptocylindrus danicus were dominant), dinoflagellates belonging to 7 genera consisting of 25 species (Prorocentrum balticum and Gymnodinium spp. were dominant) and ciliates belonging to 7 genera consisting of 8 species (Strobilidium spp. and Strombidium spp. were dominant) were identified. Within the microplankton species, there were 11 species with abundances that increased after the SWE, while there was no species with an abundance that decreased following the SWE. It is conjectured that atmospheric turbulences, such as that of an SWE, may supply sufficient nutrients to the surface layer that subsequently enhance the small bloom under the weak stratification of the Chukchi Sea Shelf during the autumn months. After the bloom, the dominant diatom community then shifts from centric-dominated to one where centric/pennate are more equal in abundance.

  4. Trophodynamics and organic matter assimilation pathways in the northeast Chukchi Sea, Alaska

    Science.gov (United States)

    McTigue, Nathan D.; Dunton, Kenneth H.

    2014-04-01

    We analyzed trophic linkages in the northeast Chukchi Sea shelf based on the stable carbon and nitrogen isotopic analysis of 39 species collected in 2009 and 2010. To decipher organic matter assimilation pathways, benthic fauna were first categorized into nine trophic guilds based on their physical location in the seabed (epibenthic, surface, or subsurface), feeding mode (suspension feeder, deposit feeder, predator, or scavenger), and food source (suspended particulate organic matter, phytoplankton, zooplankton, sediment, microflora, meiofauna, or macrofauna). A discriminant function analysis (DFA) determined that feeding modes were predicted by stable isotope values at an overall classification success rate of 42%, although classification success of each individual guild varied from 0 to 66%. In some instances, stable isotopes classified trophic guilds incorrectly more often than correctly, suggesting high trophic redundancy in the system. A striking pattern was observed where the δ13C values of individuals in some trophic guilds, ranging from about -23 to -17‰, were substantially more 13C-enriched than representative end-members, which includes phytoplankton (-24.0‰), suspended particulate organic matter (-24.3‰), and bulk sediment organic matter (-23.3‰). In contrast, near-seafloor suspended particulate organic matter was significantly 13C-enriched compared to suspended particulate organic matter of near surface waters (p<0.05), and bulk sedimentary organic matter was more 13C-enriched than overlying phytoplankton at seven of 10 stations. This suggests the presence of an unmeasured 13C-enriched end-member that is a product of biogeochemical alteration and reworking by the sediment microbial community. Although the microbial community is difficult to quantify using bulk stable isotope analytical techniques, these results indicate it cannot be overlooked as a critical component and avenue through which large amounts of reduced carbon are assimilated by a

  5. Bacterial community structure and functional potential in the northeastern Chukchi Sea

    Science.gov (United States)

    McFarlin, Kelly M.; Questel, Jennifer M.; Hopcroft, Russell R.; Leigh, Mary Beth

    2017-03-01

    We performed a molecular microbial ecological analysis in the northeastern Chukchi Sea in order to characterize bacterial community structure and genetic potential for biogeochemical cycling and oil biodegradation in a region targeted for oil and gas exploration (Burger lease area). Samples were collected from the surface, middle (20 m), and bottom (2-3 m above seafloor) of the water column during the open-water season of August and September 2012 at 17 different locations. We determined bacterial community structure with 16S rRNA genes sequencing and detected functional genes, including an array of oil biodegradation and biogeochemical cycling (carbon, nitrogen and phosphorus cycling) genes, using the GeoChip 5.0 microarray, and then correlated molecular data to contextual physical and biogeochemical factors. Bacterial community structure differed significantly by depth (surface water vs. bottom water) and between sampling dates (August vs. September). While the relative abundance of major functional gene categories did not differ with depth, the abundance of individual functional genes for carbon cycling, nitrogen cycling, organic contaminant remediation, phosphorus cycling, sulfur cycling, virulence, and viruses differed between surface and bottom seawater samples. Aerobic oil degradation genes and taxa known to include oil-degrading bacteria were found at all three depths. These findings support previous observations that two different water masses contribute to a stratified water column in the summer open-water season of the Burger lease area, but indicate that potential function is fairly similar with depth despite differences in temperature, water chemistry, bacterial community structure, and individual functional gene alleles.

  6. High resolution Holocene sea ice records from Herald Canyon, Chukchi Sea

    Science.gov (United States)

    Pearce, Christof; Jakobsson, Martin; O'Regan, Matt; Rattray, Jayne; Barrientos, Natalia; Muchitiello, Francesco; Smittenburg, Rienk; Cronin, Tom; Coxall, Helen; Semiletov, Igor

    2016-04-01

    Arctic Ocean sea ice plays a critical role in the Earth's climate system because of the positive ice-albedo feedback mechanisms as well as its control on ocean-atmospheric heat exchange and potential influence on the thermohaline circulation. Key to improving our understanding of Arctic sea ice cover and its reaction to external forcing is the reconstruction of past variability through paleo-records such as marine sediment cores. Although the observed recent sea ice loss seems to be the strongest of the last millennia, it is still uncertain whether the shift from perennial to seasonal ice cover expected for the near future was unprecedented during the current interglacial. High resolution sea ice reconstructions from the Arctic Ocean are rare, and specifically records from the Russian Arctic are underrepresented. In this study, we present results from marine sediment cores from the Herald Canyon in the East Siberian Sea. The area is one of the major conduits of Pacific water entering the Arctic Ocean basin from the Bering Strait and is thus an ideal place to study past variability of the inflow of these nutrient rich waters. Radiocarbon dating of mollusks indicates very high sedimentation rates at the coring sites which allowed for analyses at centennial resolution up to decadal resolution in the late Holocene. Core samples were analyzed for the biomarker IP25, which is produced by diatoms living in sea ice and is used as a proxy of past seasonal sea ice concentrations. Preliminary results indicate the presence of seasonal sea ice during the entire Late Holocene and show a significant increase of sea ice concentrations during the last millennia.

  7. Sea-ice algae: Major contributors to primary production and algal biomass in the Chukchi and Beaufort Seas during May/June 2002

    Science.gov (United States)

    Gradinger, Rolf

    2009-08-01

    Sea-ice and water samples were collected at 14 stations on the shelves and slope regions of the Chukchi and Beaufort Seas during the spring 2002 expedition as part of the Shelf-Basin Interaction Studies. Algal pigment content, particulate organic carbon and nitrogen, and primary productivity were estimated for both habitats based on ice cores, brine collection and water samples from 5-m depth. The pigment content (0.2-304.3 mg pigments m -2) and primary productivity (0.1-23.0 mg C m -3 h -1) of the sea-ice algae significantly exceeded water-column parameters (0.2 and 1.0 mg pigments m -3; food availability for herbivores in early spring in the Chukchi and Beaufort Seas. Stable isotope signatures for ice and water samples did not differ significantly for δ 15N, but for δ 13C (ice: -25.1‰ to -14.2‰; water: -26.1‰ to -22.4‰). The analysis of nutrient concentrations and the pulse-amplitude-modulated fluorescence signal of ice algae and phytoplankton indicate that nutrients were the prime limiting factor for sea-ice algal productivity. The estimated spring primary production of about 1-2 g C m -2 of sea-ice algae on the shelves requires the use of substantial nutrient reservoirs from the water column.

  8. Decadal to millennial-scale variability in sea ice, primary productivity, and Pacific-Water inflow in the Chukchi/East Siberian Sea area (Arctic Ocean)

    Science.gov (United States)

    Stein, Ruediger; Fahl, Kirsten; Matthiessen, Jens; Méheust, Marie; Nam, Seung-il; Niessen, Frank; Schade, Inka; Schreck, Michael; Wassmuth, Saskia; Xiao, Xiaotong

    2014-05-01

    Sea-ice is an essential component of the global climate system and, especially, the Polar Oceans. An alarming decrease in term of sea-ice concentration, thickness and duration, has been observed in the Arctic Ocean and its marginal seas over the last 30 years. Thus, understanding the processes controlling modern sea-ice variability and reconstructing paleo-sea-ice extent and variability in polar regions have become of great interest for the international scientific community during the last years. Here, we present new proxy records determined in sediment cores from the East Siberian Sea (RV Polarstern Expedition ARK-XXIII/3 in 2008; Core PS72/350) and from the Chukchi Sea (RV Araon Expedition ARA2B in 2011; Core ARA2B-1A, -1B). These records, including organic-geochemical bulk parameters, specific biomarkers (IP25 and sterols; PIP25; for recent reviews see Stein et al., 2012; Belt and Müller, 2013), biogenic opal, mineralogical data as well as high-resolution XRF scanning data, give new insight into the short-term (decadal-, centennial- to millennial-scale) variability in sea-ice, primary productivity and Pacific-Water inflow during Holocene times. Maximum concentrations of phytoplankton biomarkers and biogenic opal were determined between 8.5 and 4 kyrs. BP, suggesting enhanced primary productivity triggered by increased inflow of nutrient-rich Pacific Water (and/or an increased nutrient input due to an ice-edge position). Short-lived peak values in productivity might be related to strong pulses of Pacific-Water input during this time period (cf., Ortiz et al., 2009). A seasonal sea-ice cover was present in the Chukchi Sea throughout the last 10 kyrs. During the last 3-4 kyrs. BP, the sea-ice cover significantly extended. References Belt, S.T. and Müller, J., 2013. The Arctic sea ice biomarker IP25: a review of current understanding, recommendations for future research and applications in palaeo sea ice reconstructions. Quaternary Science Review 73, 9-25. Ortiz

  9. Underwater Acoustic Localization and Tracking of Pacific Walruses in the Northeastern Chukchi Sea

    Science.gov (United States)

    Rideout, Brendan Pearce

    This thesis develops and demonstrates an approach for estimating the three-dimensional (3D) location of a vocalizing underwater marine mammal using acoustic arrival time measurements at three spatially separated receivers while providing rigorous location uncertainties. To properly account for uncertainty in the measurements of receiver parameters (e.g., 3D receiver locations and synchronization times) and environmental parameters (water depth and sound speed correction), these quantities are treated as unknowns constrained with prior estimates and prior uncertainties. While previous localization algorithms have solved for an unknown scaling factor on the prior uncertainties as part of the inversion, in this work unknown scaling factors on both the prior and arrival time uncertainties are estimated. Maximum a posteriori estimates for sound source locations and times, receiver parameters, and environmental parameters are calculated simultaneously. Posterior uncertainties for all unknowns are calculated and incorporate both arrival time and prior uncertainties. Simulation results demonstrated that, for the case considered here, linearization errors are generally small and that the lack of an accurate sound speed profile does not necessarily cause large uncertainties or biases in the estimated positions. The primary motivation for this work was to develop an algorithm for locating underwater Pacific walruses in the coastal waters around Alaska. In 2009, an array of approximately 40 underwater acoustic receivers was deployed in the northeastern Chukchi Sea (northwest of Alaska) from August to October to record the vocalizations of marine mammals including Pacific walruses and bowhead whales. Three of these receivers were placed in a triangular arrangement approximately 400 m apart near the Hanna Shoal (northwest of Wainwright, Alaska). A sequence of walrus knock vocalizations from this data set was processed using the localization algorithm developed in this thesis

  10. Short-term changes in a microplankton community in the Chukchi Sea during autumn: consequences of a strong wind event

    Directory of Open Access Journals (Sweden)

    N. Yokoi

    2015-06-01

    Full Text Available An increase in atmospheric turbulence in the Chukchi Sea due to the recent drastic sea-ice reduction during summer months has been reported. The importance of the effects of this atmospheric turbulence on the marine ecosystem in this region, however, is not fully understood. To evaluate the effects of atmospheric turbulence on the marine ecosystem, high-frequency sampling (daily from five layers of the microplankton community between 0 and 30 m at a fixed station in the Chukchi Sea from 10 through 25 September 2013 was conducted. During the study period, a strong wind event (SWE was observed on 18 and 19 September. The abundance of microplankton was 2.6 to 17.6 cells mL−1, with a maximum abundance reported at 20 m on 22 September, while diatoms were the most dominant taxa throughout the study period. The abundances of diatoms, dinoflagellates and ciliates ranged between 1.6 and 14.1, 0.5 and 2.4 cells mL−1 and 0.1 and 2.8 cells mL−1, respectively. Diatoms belonging to seven genera consisting of 35 species (Cylindrotheca closterium and Leptocylindrus danicus were dominant, dinoflagellates belonging to seven genera consisting of 25 species (Prorocentrum balticum and Gymnodinium spp. were dominant and ciliates belonging to seven genera consisting of eight species (Strobilidium spp. and Strombidium spp. were dominant were identified. Within the microplankton species, there were 11 species whose abundance increased after the SWE, while there was no species whose abundance decreased following the SWE. It is conjectured that atmospheric turbulences, such as that of an SWE, may supply sufficient nutrients to the surface layer that then enhance the small bloom under the weak stratification of the Chukchi Sea shelf during the autumn months. After the bloom, the dominant diatom community then shifts from a centric diatom to a pennate diatom, thus suggesting that an SWE accelerates the seasonal succession of the microplankton community from summer to

  11. Spatial heterogeneity in zooplankton summer distribution in the eastern Chukchi Sea in 2012-2013 as a result of large-scale interactions of water masses

    Science.gov (United States)

    Pinchuk, Alexei I.; Eisner, Lisa B.

    2017-01-01

    Interest in the Arctic shelf ecosystems has increased in recent years as the climate has rapidly warmed and sea ice declined. These changing conditions prompted the broad-scale multidisciplinary Arctic Ecosystem integrated survey (Arctic Eis) aimed at systematic, comparative analyses of interannual variability of the shelf ecosystem. In this study, we compared zooplankton composition and geographical distribution in relation to water properties on the eastern Chukchi and northern Bering Sea shelves during the summers of 2012 and 2013. In 2012, waters of Pacific origin prevailed over the study area carrying expatriate oceanic species (e.g. copepods Neocalanus spp., Eucalanus bungii) from the Bering Sea outer shelf well onto the northeastern Chukchi shelf. In contrast, in 2013, zooplankton of Pacific origin was mainly distributed over the southern Chukchi shelf, suggesting a change of advection pathways into the Arctic. These changes also manifested in the emergence of large lipid-rich Arctic zooplankton (e.g. Calanus hyperboreus) on the northeastern Chukchi shelf in 2013. The predominant copepod Calanus glacialis was composed of two distinct populations originating from the Bering Sea and from the Arctic, with the Arctic population expanding over a broader range in 2013. The observed interannual variability in zooplankton distribution on the Chukchi Sea shelf may be explained by previously described systematic oceanographic patterns derived from long-term observations. Variability in oceanic circulation and related zooplankton distributions (e.g. changes in southwestward advection of C. hyperboreus) may impact keystone predators such as Arctic Cod (Boreogadus saida) that feed on energy-rich zooplankton.

  12. Estimating Arctic sea-ice freeze-up and break-up from the satellite record: A comparison of different approaches in the Chukchi and Beaufort Seas

    Directory of Open Access Journals (Sweden)

    Mark Johnson

    2016-09-01

    Full Text Available 1. Abstract The recognized importance of the annual cycle of sea ice in the Arctic to heat budgets, human behavior, and ecosystem functions, requires consistent definitions of such key events in the ice cycle as break-up and freeze-up. An internally consistent and reproducible approach to characterize the timing of these events in the annual sea-ice cycle is described. An algorithm was developed to calculate the start and end dates of freeze-up and break-up and applied to time series of satellite-derived sea-ice concentration from 1979 to 2013. Our approach builds from discussions with sea-ice experts having experience observing and working on the sea ice in the Bering, Chukchi and Beaufort Seas. Applying the algorithm to the 1979–2013 satellite data reveals that freeze-up is delayed by two weeks per decade for the Chukchi coast and one week per decade for the Beaufort coast. For both regions, break-up start is arriving earlier by 5–7 days per decade and break-up end is arriving earlier by 10–12 days per decade. In the Chukchi Sea, “early” break-up is arriving earlier by one month over the 34-year period and alternates with a “late” break-up. The calculated freeze-up and break-up dates provide information helpful to understanding the dynamics of the annual sea-ice cycle and identifying the drivers that modify this cycle. The algorithm presented here, and potential refinements, can help guide future work on changes in the seasonal cycle of sea ice. The sea-ice phenology of freeze-up and break-up that results from our approach is consistent with observations of sea-ice use. It may be applied to advancing our understanding and prediction of the timing of seasonal navigation, availability of ice as a biological habitat, and assessment of numerical models.

  13. Occurrence of polychlorinated biphenyls (PCBs) together with sediment properties in the surface sediments of the Bering Sea, Chukchi Sea and Canada Basin.

    Science.gov (United States)

    Hong, Qingquan; Wang, Yun; Luo, Xiaojun; Chen, Shejun; Chen, Jigang; Cai, Minghong; Cai, Minggang; Mai, Bixian

    2012-09-01

    The spatial distribution and potential source of polychlorinated biphenyls (PCBs) in surface sediments from Bering Sea, Chukchi Sea, and Canada Basin and the relationship between PCBs and sedimentary properties including grain size, water content, loss on ignition, total organic carbon, and black carbon were explored. ΣPCBs (the sum of the detected PCB congeners) concentrations fluctuated in the study area, ranging from 22-150, 60-640 and 24-600 pg g(-1) dry weight for the Bering Sea, Chukchi Sea, and Canada Basin. A similar homologue pattern was observed at different locations, with tri-chlorinated PCBs being the dominant homologue, implying that the PCBs came mainly from the atmospheric transportation and deposition and ocean current transportation. No apparent co-relationships between PCB concentrations and sediment properties were obtained, indicating that the distribution of PCBs was not only controlled by their source, but also by the multi-factors such as atmospheric transport and depositing, mixing, partitioning and sorption in the water column and sediments.

  14. China' s First Exploration of Chukchi Sea and Its Adjacent Waters in the Arctic- A Study on Lead Geochemistry of Atmospheric Aerosol

    Institute of Scientific and Technical Information of China (English)

    朱赖民; 陈立奇

    2003-01-01

    The Pb concentrations of atmospheric aerosol in the Chukchi Sea of the Arctic varywithin the range of 0. 167 -0.962 ng/m3, with an average of 0.532 ng/m3. These concentra-tion values are 200 times higher than the natural background values of snow samples there. Cal-culation of the Pb enrichment factor of aerosol indicates that the ocean- and continent-sourcelead account for 9.23% and 0.01%, respectively, but industrially released Pb accounts formore than 90% of the atmospheric Pb. The Pb isotopic composition of aerosol has revealed thatthe sources of lead from industrial lead that causes pollution include mainly the western part ofNorth America, East Europe and the former Soviet Union. The calculation of the total falloutflux of Pb indicates that the mean value of input flux into the Chukchi Sea is 0.02 mgm-2a-1,equivalent to that of southern Pacific but slightly lower than that of northern Indian Sea andsouthern Atlantic. It is evidenced that the Pb input flux into the Chukchi Sea is far lower thanthat off the Baltic Sea, the North Sea and the Mediterranean Sea.

  15. Benthic Food Webs of the Chukchi and Beaufort Seas: Relative Importance of Ultimate Carbon Sources in a Changing Climate

    Science.gov (United States)

    Dunton, K. H.; Schonberg, S. V.; Mctigue, N.; Bucolo, P. A.; Connelly, T. L.; McClelland, J. W.

    2014-12-01

    Changes in sea-ice cover, coastal erosion, and freshwater run-off have the potential to greatly influence carbon assimilation pathways and affect trophic structure in benthic communities across the western Arctic. In the Chukchi Sea, variations in the duration and timing of ice cover affect the delivery of ice algae to a relatively shallow (40-50 m) shelf benthos. Although ice algae are known as an important spring carbon subsidy for marine benthic fauna, ice algal contributions may also help initiate productivity of an active microphytobenthos. Recent studies provide clear evidence that the microphytobenthos are photosynthetically active, and have sufficient light and nutrients for in situ growth. The assimilation of benthic diatoms from both sources may explain the 13C enrichment observed in benthic primary consumers throughout the northern Chukchi. On the eastern Beaufort Sea coast, shallow (2-4 m) estuarine lagoon systems receive massive subsidies of terrestrial carbon that is assimilated by a benthic fauna of significant importance to upper trophic level species, but again, distinct 13C enrichment in benthic primary consumers suggests the existence of an uncharacterized food source. Since ice algae are absent, we believe the 13C enrichment in benthic fauna is caused by the assimilation of benthic microalgae, as reflected in seasonally high benthic chlorophyll in spring under replete light and nutrient conditions. Our observations suggest that changes in ice cover, on both temporal and spatial scales, are likely to have significant effects on the magnitude and timing of organic matter delivery to both shelf and nearshore systems, and that locally produced organic matter may become an increasingly important carbon subsidy that affects trophic assimilation and secondary ecosystem productivity.

  16. Current meter and other data from meters on fixed platforms from the Chukchi Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 14 July 1985 to 04 October 1987 (NODC Accession 8800032)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter and other data were collected from meters on NOAA Ship OCEANOGRAPHER AND NOAA Ship SURVEYOR in the Chukchi Sea by the University of Alaska - Fairbanks;...

  17. Benthic organisms data collected using sediment sampler casts from NOAA Ship OCEANOGRAPHER in the Chukchi Sea from 1986-09-06 to 1987-10-05 (NCEI Accession 8900299)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organisms data were collected using sediment sampler casts from NOAA Ship OCEANOGRAPHER in the Chukchi Sea from 06 September 1986 to 05 October 1987. Data...

  18. l1182cs.m77t - MGD77 data file for Geophysical data from field activity L-11-82-CS in Chukchi Sea, Alaska from 08/27/1982 to 09/16/1982

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-11-82-CS in Chukchi Sea, Alaska from...

  19. Surface currents and temperature data from satellite-tracked drifters in the Chukchi and Beaufort Seas from 2011-08-07 to 2014-03-06 (NODC Accession 0126984)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifters were deployed from vessels in the Chukchi Sea during the ice-free seasons of 2011-2013. Drifter positions were determined via GPS, and positions were...

  20. Marine mammal observations collected by aircraft and ship and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas, 2006-2010 (NODC Accession 0120532)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains vessel- and aircraft-based mammal sightings data and associated environmental data collected in the Chukchi and Beaufort seas during the open...

  1. Acoustics short-term passive monitoring using sonobuoys in the Bering, Chukchi, and Western Beaufort Seas conducted by Alaska Fisheries Scientific Center, National Marine Mammal Laboratory from 2007-08-01 to 2015-09-28 (NCEI Accession 0138863)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine spatio-temporal...

  2. Marine Fish and Shellfish Survey data from otter trawls in the Chukchi Sea from the OCEAN HOPE 3 and OSHORO MARU from 16 August 1990 to 31 July 1992 (NODC Accession 9400061)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine Fish and Shellfish Survey data were collected from otter trawls in the Chukchi Sea from the OCEAN HOPE. Data were collected by the University of Alaska from...

  3. Drifting buoy and other data from the Chukchi Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 27 June 1977 to 07 November 1977 (NODC Accession 7800005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy data was collected from the Chukchi Sea by the University of Washington (UW) as part of the Outer Continental Shelf Environmental Assessment Program...

  4. Marine mammal observations collected by aircraft and ship and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas, 2006-2007 (NODC Accession 0120531)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set was collected as part of the Joint Monitoring Program during seismic activities in the Chukchi Sea. The 2006 data was collected by ship and aircraft as...

  5. Marine bird sighting and other data from aircraft in the Eastern Chukchi Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 July 1978 to 20 August 1978 (NODC Accession 8200032)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from aircraft in the Eastern Chukchi Sea from 25 July 1978 to 20 August 1978. Data were collected by the...

  6. Surface and basal sea ice melt from autonomous buoy arrays during the 2014 sea ice retreat in the Beaufort/Chukchi Seas

    Science.gov (United States)

    Maksym, T. L.; Wilkinson, J.; Hwang, P. B.

    2014-12-01

    As the Arctic continues its transition to a seasonal ice cover, the nature and role of the processes driving sea ice retreat are expected to change. Key questions revolve around how the coupling between dynamics and thermodynamic processes and potential changes in the role of melt ponds contribute to an accelerated seasonal ice retreat. To address these issues, 44 autonomous platforms were deployed in four arrays in the Beaufort Sea in March, 2014, with an additional array deployed in August in the Chukchi Sea to monitor the evolution of ice conditions during the seasonal sea ice retreat. Each "5-dice" array included four or five co-sited ice mass balance buoys (IMB) and wave buoys with digital cameras, and one automatic weather station (AWS) at the array center. The sensors on these buoys, combined with satellite imagery monitoring the large-scale evolution of the ice cover, provide a near-complete history of the processes involved in the seasonal melt of sea ice. We present a preliminary analysis of the contributions of several key processes to the seasonal ice decay. The evolution of surface ponding was observed at several sites with differing ice types and surface morphologies. The records of surface melt and ice thickness demonstrate a key role of ice type in driving the evolution of the ice cover. Analysis of the surface forcing and estimates of solar energy partitioning between the surface and upper ocean is compared to the surface and basal mass balance from the IMBs. The role of ice divergence and deformation in driving sea ice decay - in particular its role in accelerating thermodynamic melt processes - is discussed.

  7. Late Pleistocene glacio-marine sedimentation in the Chukchi Sea, the western Arctic Ocean

    Science.gov (United States)

    Yoon, Seok-Hoon; Joe, Young-Jin; Nam, Seung-Il

    2013-04-01

    In this study, we present the results of sedimentary and echo facies analyses of gravity cores and high-resolution sub-bottom profiling (SBP) data obtained during the 2011 Arctic expedition of R/V Araon (operated by KOPRI) in the Chukchi Sea, the western part of the Arctic Ocean. The gravity cores (248-548 cm long) at 3 stations were collected from the continental shelf and slope areas of the sea, and X-radiographs of sediment slabs were taken from the lengthwise-cut split cores to observe sedimentary structures. Grain size of core sediment was analyzed using standard sieves and a Micrometrics Sedigraph 5000D. High-resolution sub-bottom profiling (SBP) survey was also deployed during the Araon cruise to obtain information on seafloor topography and acoustic characteristics of subsurface sedimentary sequences. On the SBP data (ca. 70 m of the penetration depth), 3 stratigraphic units (SU-1, 2, 3 in ascending order) are recognized by 2 distinctive reflectors within the sequence. In some places, the lowermost boundary (5-20 m deep below seafloor) between SU-1 and 2 is characterized by channel-shaped erosional topography, which is interpreted to have been originated from incision by grounded glaciers or fluvial channels during the sea-level lowstand, most probably LGM. The boundary between SU-2 and 3 is characterized by a prolonged reflection with a relatively flat and low-relief topography in the inner continental shelf, whereas it gradually changes into a higher-relief reflector with small hummocks in the outer shelf and slope areas. Such acoustic and topographic characters are interpreted to indicate the irregular surface of cohesive mass-flow deposits (e.g. debrites and slump deposits). More specifically, the acoustic characters in the SBP data are classified into 5 echo facies on the basis of clarity, continuity, and shape of bottom and sub-bottom echoes together with seafloor topography. Echo facies IIA is most prominent type in SU-3 recorded from the continental

  8. A comparison between late summer 2012 and 2013 water masses, macronutrients, and phytoplankton standing crops in the northern Bering and Chukchi Seas

    Science.gov (United States)

    Danielson, Seth L.; Eisner, Lisa; Ladd, Carol; Mordy, Calvin; Sousa, Leandra; Weingartner, Thomas J.

    2017-01-01

    Survey data from the northern Bering and Chukchi sea continental shelves in August-September 2012 and 2013 reveal inter-annual differences in the spatial structure of water masses along with statistically significant differences in thermohaline properties, chemical properties, and phytoplankton communities. We provide a set of water mass definitions applicable to the northern Bering and Chukchi continental shelves, and we find that the near-bottom Bering-Chukchi Summer Water (BCSW) was more saline in 2012 and Alaskan Coastal Water (ACW) was warmer in 2013. Both of these water masses carried higher nutrient concentrations in 2012, supporting a larger chlorophyll a biomass that was comprised primarily of small (ice in winter and early spring in 2012 and 2013 resembled conditions of the 1980s and early 1990s but the regional ice retreat rate has accelerated in the late 1990s and 2000s so the summer and fall ice concentrations more closely resembled those of the last two decades. Our data show that wind forcing can shut down the Alaskan Coastal Current in the NE Chukchi Sea for periods of weeks to months during the ice-covered winter and during the summer when buoyancy forcing is at its annual maximum. We hypothesize that a decrease in salinity and nutrients from 2012 to 2013 was a consequence of a decreased net Bering Strait transport from 2011 to 2012. Biological ramifications of an accelerated ice melt-back, restructuring of shelf flow pathways, and inter-annually varying Bering Strait nutrient fluxes are mostly unknown but all of these variations are potentially important to the Arctic ecosystem. Our results have implications for the total magnitude and seasonal evolution of primary productivity, secondary production, and the fate of fresh water, heat, and pelagic production on the Bering-Chukchi shelves.

  9. Wind-driven mixing causes a reduction in the strength of the continental shelf carbon pump in the Chukchi Sea (Invited)

    Science.gov (United States)

    Hauri, C.

    2013-12-01

    Dynamic and complex physical and biological processes drive the carbonate system chemistry of the Chukchi Sea. The inflow of nutrient-rich Pacific water through the Bering Straight and sustained periods of solar radiation in summer turn this polar shelf into one of the most productive ecosystems in the world. High rates of primary production (~ 470 g C m-2 y-1) and low pelagic grazing rates draw down pCO2 at the surface and support large fluxes of organic carbon to a rich benthic ecosystem. Much of this carbon is remineralized, leading to elevated pCO2 in bottom and subsurface waters, which are thought to be isolated from the atmosphere by strong stratification. Subsequent shelf to basin transport of remineralized carbon and organic matter into the interior Arctic Ocean are believed to support a globally important CO2 sink, as well as maintain high pCO2 levels in bottom waters along their circulation-driven northward journey. Here, I document a new mechanism of carbon cycling in the Chukchi Sea that substantially reduces the net strength of this globally significant carbon sink. Surface pCO2 measurements and wind analysis suggest that annually occurring storm-induced mixing events during autumn months disrupt water column stratification and mix remineralized carbon from subsurface waters to the surface, leading to strong outgassing of CO2 to the atmosphere. This newly observed physical driver weakens the estimated strength of the continental shelf carbon pump in the Chukchi Sea from an uptake of 38 Tg C y-1 to 18-27 Tg C y-1 and revises our knowledge of the dynamics of carbon cycling on this polar shelf. An improved understanding of the distribution and transport of carbon on the shelf is crucial to elucidate how the Chukchi Sea will respond to ongoing ocean acidification and climate change.

  10. Short-term changes of the mesozooplankton community and copepod gut pigment in the Chukchi Sea in autumn

    Science.gov (United States)

    Matsuno, K.; Yamaguchi, A.; Nishino, S.; Inoue, J.; Kikuchi, T.

    2015-03-01

    In the Chukchi Sea, due to the recent drastic reduction of sea-ice during the summer, an increasing formation of atmospheric turbulence has been reported. However, the importance and effects of atmospheric turbulence on the marine ecosystem are not fully understood in this region. To evaluate the effect of atmospheric turbulence on the marine ecosystem, high-frequent sampling (two to four times per day) on the mesozooplankton community and the gut pigment of dominant copepods were made at a fixed station in the Chukchi Sea from 10 to 25 September 2013. During the study period, a strong wind event (SWE) was observed on 18 September. After the SWE, the standing stock of chlorophyll a (chl a) was increased, especially for micro-size (> 10 μm) fractions. Zooplankton abundance ranged 23 610-56 809 ind. m-2 and exhibited no clear changes with SWE. In terms of abundance, calanoid copepods constituted the most dominated taxa (mean: 57%), followed by barnacle larvae (31%). Within the calanoid copepods, small-sized Pseudocalanus spp. (65%) and large-sized Calanus glacialis (30%) dominated. In the population structure of C. glacialis, copepodid stage 5 (C5) dominated, and the mean copepodid stage did not vary with SWE. The dominance of accumulated lipids in C5 and C6 females with immature gonads indicated that they were preparing for seasonal diapause. The gut pigment of C. glacialis C5 was higher at night and was correlated with ambient chl a, and a significant increase was observed after SWE (2.6 vs. 4.5 ng pigment ind.-1). Assuming C : Chl a ratio, the grazing impact by C. glacialis C5 was estimated to be 4.14 mg C m-2 day-1, which corresponded to 0.5-4.6% of the standing stock of micro-size phytoplankton. Compared with the metabolic food requirement, their feeding on phytoplankton accounted for 12.6% of their total food requirement. These facts suggest that C. glacialis could not maintain their population on solely phytoplankton food, and other food sources (i

  11. Mercury in the northeastern Chukchi Sea: Distribution patterns in seawater and sediments and biomagnification in the benthic food web

    Science.gov (United States)

    Fox, Austin L.; Hughes, Emily A.; Trocine, Robert P.; Trefry, John H.; Schonberg, Susan V.; McTigue, Nathan D.; Lasorsa, Brenda K.; Konar, Brenda; Cooper, Lee W.

    2014-04-01

    Mercury contamination in the atmosphere, snow and marine mammals of the Arctic has been a continuing environmental concern and the focus of many investigations. Much less is known about the distribution of Hg in seawater, sediments and organisms from lower trophic levels in the Arctic, especially the Chukchi Sea. The onset of sea-ice retreat, severe coastal erosion, enhanced primary productivity and offshore energy development in the northeastern Chukchi Sea (NECS) signal changes to a system for which we have limited data for potentially toxic chemicals. To help us better understand and explain any future changes, we present here a combined data set for Hg in seawater, sediments and the following organisms from the NECS: amphipods (Ampelisca macrocephala), clams (Astarte borealis), snow crabs (Chionoecetes opilio), arctic cod (Boreogadus saida) and whelks (Buccinum spp. and Neptunea heros). Concentrations of total dissolved Hg (THgd) averaged (±standard deviation) 2.8±1.4 pM in the NECS, ~2 times greater than values of 1.5±0.5 pM for the Bering Strait. Overall, consistently lower concentrations of THgd were found at depths with markedly higher concentrations of chlorophyll a. Concentrations of total Hg (THg) in sediments from the NECS averaged 31±10 ng g-1, correlated well with silt+clay, Al and TOC, and showed a long-term record consistent with the natural, background environment. Very localized occurrences of sediment with elevated THg concentrations were identified near two exploratory drilling sites where drilling mud and formation cuttings were discharged in 1989. Concentrations of sediment monomethylmercury (MMHg) averaged 0.15±0.07 ng g-1 and accounted for only 0.43±0.17% of the sediment THg. The lowest average value (± standard error) for THg in biota was found for A. borealis at 44±4 ng g-1 dry weight (d. wt.) with 33% of the THg present as MMHg. The highest average values for THg were identified for the whelks N. heros (195±29 ng g-1, d. wt) and

  12. Composition of fish species in the Bering and Chukchi Seas and their responses to changes in the ecological environment

    Institute of Scientific and Technical Information of China (English)

    LIN Longshan; CHEN Yongjun; LIAO Yunchih; ZHANG Jing; SONG Puqing; YU Xingguang; WU Risheng; SHAO Kwang-tsao

    2014-01-01

    Based on trawl surveys in the Bering Sea and Chukchi Sea during the 2010 Chinese National Arctic Research Expedition, fish biodiversity characteristics, such as fish composition, dominant species, biodiversity, and faunal characteristics were conducted. We also discussed the responses of fishes to the quick changes in Arctic climate. The results showed that a total of 41 species in 14 families were recorded in these waters. The dominant species were Hippoglossoides robustus, Boreogadus saida, Myoxocephalus scorpius, Lumpenus fa-bricii, and Artediellus scaber. There were 35 coldwater species, accounting for 85.37%, and six cold temperate species, occupying 14.63%. The habitat types of fish could be grouped as follows:35 species of demersal fish-es, five benthopelagic fishes, and one pelagic fish. The Shannon-Wiener diversity index (H′) (range between 0 and 2.18, 1.21 on average) was not high, and descended from south to north. Climate change has caused some fishes to shift along their latitudinal and longitudinal distribution around the Arctic and Subarctic areas, and this could lead to the decline of Arctic fishery resources.

  13. Seasonal spatial patterns in seabird and marine mammal distribution in the eastern Chukchi and western Beaufort seas: Identifying biologically important pelagic areas

    Science.gov (United States)

    Kuletz, Kathy J.; Ferguson, Megan C.; Hurley, Brendan; Gall, Adrian E.; Labunski, Elizabeth A.; Morgan, Tawna C.

    2015-08-01

    The Chukchi and Beaufort seas are undergoing rapid climate change and increased human activity. Conservation efforts for upper trophic level predators such as seabirds and marine mammals require information on species' distributions and identification of important marine areas. Here we describe broad-scale distributions of seabirds and marine mammals. We examined spatial patterns of relative abundance of seabirds and marine mammals in the eastern Chukchi and western Beaufort seas during summer (15 June-31 August) and fall (1 September-20 November) from 2007 to 2012. We summarized 49,206 km of shipboard surveys for seabirds and 183,157 km of aerial surveys for marine mammals into a grid of 40-km × 40-km cells. We used Getis-Ord Gi∗ hotspot analysis to test for cells with higher relative abundance than expected when compared to all cells within the study area. We identified cells representing single species and taxonomic group hotspots, cells representing hotspots for multiple species, and cells representing hotspots for both seabirds and marine mammals. The locations of hotspots varied among species but often were located near underwater canyons or over continental shelf features and slopes. Hotspots for seabirds, walrus, and gray whales occurred primarily in the Chukchi Sea. Hotspots for bowhead whales and other pinnipeds (i.e., seals) occurred near Barrow Canyon and along the Beaufort Sea shelf and slope. Hotspots for belugas occurred in both the Chukchi and Beaufort seas. There were three hotspots shared by both seabirds and marine mammals in summer: off Wainwright in the eastern Chukchi Sea, south of Hanna Shoal, and at the mouth of Barrow Canyon. In fall, the only identified shared hotspot occurred at the mouth of Barrow Canyon. Shared hotspots are characterized by strong fronts caused by upwelling and currents, and these areas can have high densities of euphausiids in summer and fall. Due to the high relative abundance of animals and diversity of taxa

  14. The benthic ecosystem of the northeastern Chukchi Sea: An overview of its unique biogeochemical and biological characteristics

    Science.gov (United States)

    Dunton, Kenneth H.; Grebmeier, Jacqueline M.; Trefry, John H.

    2014-04-01

    In February 2008, Lease Sale 193 generated renewed interest for oil and gas exploration in the northeastern Chukchi Sea and prompted a series of studies designed to increase our scientific knowledge of this biologically rich area. We present in this special issue the results from major field expeditions during open-water periods in the summers of 2009 and 2010. Our work focused on the biological and chemical characteristics of the benthos with the goal of establishing a strong baseline for assessing future changes that may occur in response to (1) impacts from oil and gas activities, and (2) variations in hydrography, circulation or ice retreat associated with climatic change. We found concentrations of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and 17 trace metals in sediments at natural background levels throughout the study area except at two previous (1989) drilling sites; there was no evidence that showed bioaccumulation of these substances above natural concentrations. Inorganic-N was recycled within one day throughout the water column, with evidence of substantial remineralization of organic matter in the sediments. Active efflux of sediment NO3- supports water column primary production that, in turn, sustains a rich benthos dominated by crustaceans and echinoderms that also receive, based on isotopic evidence, a benthic carbon subsidy. Benthic food webs are complex, with high trophic redundancy based on the diversity of both infaunal and epifaunal populations. The highest trophic levels in the benthos were dominated by predatory gastropods. Comparisons of gray whale and walrus distributions from aerial sightings showed a large difference between the two study years relative to the more stable benthic prey base for these animals over that period. A nearly ice-free shelf by early summer 2009 compared to 2010 revealed that walrus distributions were more closely linked to sea ice rather than to benthic prey items, indicating that rapid

  15. AFSC/ABL: Genetic analysis of juvenile chum salmon from the Chukchi Sea and Bering Strait

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Arctic region has experienced warming in recent years, resulting in decreased summer sea ice cover and increased sea surface temperatures. In 2007, the U.S....

  16. Distribution of general aerobic heterotrophic bacteria in sediment core taken from the Canadian basin and the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    Gao Aiguo; Chen Haowen

    2008-01-01

    The occurrence percentage and abundance of General Aerobic Heterotrophic Bacteria (GAB) were determined by using the method of MPN for 182 subsamples from 10 sediment cores taken from the Canadian basin and the Chukchi Sea at two different culturing temperatures.The results showed that the general occurrencepercentage of GAB was quite high,average abundances of GAB at cultured temperatures of 4℃ and 25℃ were 4.46 ×107 and 5.47×107 cells·g -1 (wt), respectively.The highest abundance of GAB occurred at 20~22 cm section in the sediment.GAB abundances changed among the section of sediments,but there is a trend: the abundances at the middle or lower sections were lower than those at upper section.Cultivation at 25℃ could improve the occurrence percentage and abundances of GAB,which suggests that the increasing of temperature may change the living circumstances of GAB.The differences of GAB among the latitudes areas indicated thatoccurrence percentage and abundances of GAB in middle latitude areas were higher than those in the higher or lower latitude areas,and were more obvious at 4℃than those at 25℃.The GAB abundances in sediment under the shallower water seemed to be lower than those in sediments under the deeper water and this status was more obvious at 25℃ than that at 4℃.

  17. The fundamental characteristics of current in the Bering Strait and the Chukchi Sea from July to September 2003

    Institute of Scientific and Technical Information of China (English)

    LI Lei; DU Ling; ZHAO Jinping; ZUO Juncheng; LI Peiliang

    2005-01-01

    The characteristics of current in the Bering Strait and the Chukchi Sea are analyzed based on the two current data on the mooring stations during the Second National Arctic Research Expedition of China in 2003. The tidal currents of the principal diurnal and semidiurnal ellipses rotate clockwise in the upper layer, except for N2, S2, and Q1 at Sta. ST. In the Bering Strait (Sta. ST), the major semi-axis of tidal current constituent M2 is 2.9 cm/s in the upper layer, which is much smaller than that of semi-monthly oscillation (11.8 cm/s);and the mean current flows northwestward at the amplitude of about 20 cm/s and varies a little with depth. During the cruise, the current has significant semi-monthly oscillation at the two mooring stations. The spectra analyses of the air pressure gradient and the wind stress show that there are the semi-monthly oscillations in these two data series. The near-inertial current, approximately 4 cm/s, presents almost the same magnitude of the principal tidal currents in the Bering Strait.

  18. Late Quaternary Provenance and Flow Regime Reconstruction through Sedimentologic and Geochemical Evidence from the Bering/Chukchi Seas

    Science.gov (United States)

    Pelto, B. M.; Brigham-Grette, J.; Kocis, J. J.; Petsch, S.

    2013-12-01

    The last 20 kyr have been marked by great changes in the Arctic, as the Laurentide Ice Sheet melted and led to the submergence of the Bering Land Bridge and the re-opening of the Bering Strait (BS). The BS is a narrow connection (about 85 km wide) between the Arctic and Pacific Oceans averaging less than 50 m in depth, with present-day flow of seawater northward through the BS, from the Pacific to the Arctic. This flow is of vital importance to global ocean circulation through its role in formation and stability of North Atlantic Deep Water (NADW). An open BS is believed to speed dispersal of North Atlantic freshwater anomalies, both by keeping thermohaline circulation strong, and through reversals of flow through the BS when the North Atlantic is hosed with freshwater. When the BS is closed, these anomalies cannot efficiently dissipate and thermohaline circulation is weakened, which is considered a factor in climate perturbations outside of orbital forcing. Given the period of flux and transition in the Arctic following the Last Glacial Maximum (LGM), the paleoceanographic history of the Bering and Chukchi Seas post-LGM, is important to an understanding of Arctic Ocean circulation, and consequent climate impacts. Today the Arctic is in a period of rapid change, multi-year sea ice is disappearing, and the continuation of climatic stability of the Holocene appears to be at an end. Comprehension of the functioning of the Arctic as a dynamic system is essential to predict future response of the system to change, such as seawater salinity-density changes, lowered sea and land albedo, and rising temperatures. Changes in BS throughflow intensity and direction during deglaciation and submergence of the Bering Land Bridge are proposed and supported in modeling simulations, and are thought to occur during millennial-scale climate changes. We have conducted a coupled sedimentological and geochemical investigation of a suite of marine sediment cores from the Bering and

  19. Modeling seasonal variations of ocean and sea ice circulation in the Beaufort and Chukchi Seas: A model-data fusion study

    Institute of Scientific and Technical Information of China (English)

    WANG Jia; Kohei Mizobata; HU Haoguo; JIN Mei-bing; ZHANG Sheng; Walter Johnson; Koji Shimada; Moto Ikeda

    2008-01-01

    A 3.8-km Coupled Ice-Ocean Model (CIOM) was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas, including the Bering-inflow-originated coastal current that splits into three branches:Alaska Coastal Water (ACW) , Central Channel, and Herald Valley branches. Other modeled phenomena include the Beaufort Slope Current (BSC) , the Beautort Gyre,the East Siberian Current (ESC), mesoscale eddies, seasonal landfast ice, sea ice ridging, shear, and deformation. Many of these downscaling processes can only be captured by using a high-resolution C1OM, nested in a global climate model. The seasonal cycles for sea ice concentration, thickness, velocity, and other variables are well reproduced with solid validation by satellite measurements. The seasonal cycles for upper ocean dynamics and thermodynamics are also well reproduced, which inelude the formation of the cold saline layer due to the injection of salt during sea ice formation, the BSC, and the subsurface upwelling in winter that brings up warm, even more saline Atlantic Water along the shelfbreak and shelf along the Beaufort coast.

  20. Zooplankton diel vertical migration and influence of upwelling on the biomass in the Chukchi Sea during summer

    Institute of Scientific and Technical Information of China (English)

    WANG Huiwu; CHEN Hongxia; XUE Liang; LIU Na; LIU Yanliang

    2015-01-01

    The diel vertical migration (DVM) of zooplankton and the influence of upwelling on zooplankton biomass were examined using water column data of current velocity and mean volume backscattering strength (MVBS) collected by moored acoustic Doppler current profilers (ADCPs) deployed in the southeastern Chukchi Sea during the 5th Chinese National Arctic Research Expedition (CHINARE) in summer 2012, combined with the satellite observational data such as sea surface temperature (SST), wind, and chlorophylla (Chla). Hourly acoustic data were continuously collected for 49-d in the mooring site. Spectral analysis indicated that there were different migrating patterns of zooplankton, even though precisely classifying the zooplankton taxa was not available. The prevailing 24-h cycle corresponded to the normal DVM with zooplankton swimming upwards at sunrise and returning to deep waters at sunset. There was a clear DVM in the upper 17 m of the water column during the period with distinct day-night cycles, and no active DVM throughout the water column when the sun above the horizon (polar day), suggesting that light intensity was the trigger for DVM. Also there was a second migrating pattern with 12-h cycle. The upwelling event occurring in the northwest of Alaskan coastal area had important influence on zooplankton biomass at the mooring site. During the upwelling, the SST close to the mooring site dropped significantly from maximal 6.35℃ to minimal 1.31℃ within five days. Simultaneously, there was a rapid increase in the MVBS and Chla level, suggesting the aggregation of zooplankton related to upwelling.

  1. Wave-Ice and Air-Ice-Ocean Interaction During the Chukchi Sea Ice Edge Advance

    Science.gov (United States)

    2015-09-30

    Ocean Heat: In the new Arctic summer ice regime, with extended open water periods in areas previously covered with sea ice, ocean heat, received...additional buoy with an 80m temperature chain for monitoring the upper ocean evolution has been built at WHOI to replace the loss of one of the UpTempo...addition was made to the Sea State field program through separate funding to Luc Rainville of APL, who will provide an underway temperature and salinity

  2. Marine-entry timing and growth rates of juvenile Chum Salmon in Alaskan waters of the Chukchi and northern Bering seas

    Science.gov (United States)

    Vega, Stacy L.; Sutton, Trent M.; Murphy, James M.

    2017-01-01

    Climate change in the Arctic has implications for influences on juvenile Chum Salmon Oncorhynchus keta early life-history patterns, such as altered timing of marine entry and/or early marine growth. Sagittal otoliths were used to estimate marine entry dates and daily growth rates of juvenile Chum Salmon collected during surface trawl surveys in summers 2007, 2012, and 2013 in the Chukchi and northern Bering seas. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to discriminate between freshwater and marine sagittal growth on the otoliths, and daily growth increments were counted to determine marine-entry dates and growth rates to make temporal and regional comparisons of juvenile Chum Salmon characteristics. Marine-entry dates ranged from mid-June to mid-July, with all region and year combinations exhibiting similar characteristics in entry timing (i.e. larger individuals at the time of capture entered the marine environment earlier in the growing season than smaller individuals in the same region/year), as well as similar mean marine-entry dates. Juvenile Chum Salmon growth rates were on average 4.9% body weight per day in both regions in summers 2007 and 2012, and significantly higher (6.8% body weight per day) in the Chukchi Sea in 2013. These results suggest that juvenile Chum Salmon in the northern Bering and Chukchi seas currently exhibit consistent marine-entry timing and early marine growth rates, despite some differences in environmental conditions between regions and among years. This study also provides a baseline of early marine life-history characteristics of Chum Salmon for comparisons with future climate change studies in these regions.

  3. CO2 cycling in the coastal ocean. I - A numerical analysis of the southeastern Bering Sea with applications to the Chukchi Sea and the northern Gulf of Mexico

    Science.gov (United States)

    Walsh, John J.; Dieterle, Dwight A.

    A quasi-two dimensional model of the carbon and nitrogen cycling above the 70m isobath of the southeastern Bering Sea at 57°N replicates the observed seasonal cycles of nitrate, ammonium, ΣCO2, pCO2, light penetration, chlorophyll, phytoplankton growth rate, and primary production, as constrained by changes in wind, incident radiation, temperature, ice cover, vertical and lateral mixing, grazing stress, benthic processing of phytodetritus and zooplankton fecal pellets, and the pelagic microbial loop of DOC, bacteria, and their predators. About half of the seasonal resupply of nitrate stocks to their initial winter conditions is derived from in situ nitrification, with the rest obtained from deep-sea influxes. Under the present conditions of atmospheric forcing, shelf-break exchange, and food web structure, this shelf ecosystem serves as a sink for atmospheric CO2, with storage in the forms of exported DOC, DIC, and unutilized POC (phytoplankton, bacteria, and fecal pellets). As a consequence of just the rising levels of atmospheric pCO2 since the the Industrial Revolution, however, the biophysical CO2 status of the Southeastern Bering Sea shelf may have switched over the last 250 years, from a prior source to the present sink, since this relatively pristine ecosystem has unergone little eutrophication. Such fluctuations of CO2 status may thus be reversed by the physical processes of : (1) reduction of atmospheric pCO2, (2) increased on welling of deep-sea ΣCO2, and (3) warming of shelf waters. Based on our application of this model to the Chukchi Sea and the Gulf of Mexico, about 1.0-1.2 gigatons C y-1 of atmospheric CO2 may now be sequestered by temperate and polar shelf ecosystems. When tropical systems are included, however, a positive net sink of only 0.6-0.8. × 1015g C y-1 may prevail over all shelves.

  4. Food habits of Arctic staghorn sculpin (Gymnocanthus tricuspis) and shorthorn sculpin (Myoxocephalus scorpius) in the northeastern Chukchi and western Beaufort Seas

    Science.gov (United States)

    Gray, Benjamin P.; Norcross, Brenda L.; Beaudreau, Anne H.; Blanchard, Arny L.; Seitz, Andrew C.

    2017-01-01

    Arctic staghorn sculpin (Gymnocanthus tricuspis) and shorthorn sculpin (Myoxocephalus scorpius) belong to Cottidae, the second most abundant fish family in the western Arctic. Although considered important in food webs, little is known about their food habits throughout this region. To address this knowledge gap, we examined and compared the diets of 515 Arctic staghorn sculpin and 422 shorthorn sculpin using stomachs collected over three summers in the northeastern Chukchi Sea (2010-2012) and one summer in the western Beaufort Sea (2011). We used permutational multivariate analysis of variance (PERMANOVA) and non-metric multidimensional scaling (nMDS) to compare sculpin diets between regions and selected size classes. Differences in mouth morphologies and predator size versus prey size relationships were examined using regression techniques. Arctic staghorn sculpin and shorthorn sculpin diet compositions differed greatly throughout the Chukchi and Beaufort Seas. Regardless of body size, the smaller-mouthed Arctic staghorn sculpin consumed mostly benthic amphipods and polychaetes, whereas the larger-mouthed shorthorn sculpin shifted from a diet composed of benthic and pelagic macroinvertebrates as smaller individuals to shrimps and fish prey as larger individuals. Within shared habitats, the sculpins appear to partition prey, either by taxa or size, in a manner that suggests no substantial overlap occurs between species. This study increases knowledge of sculpin feeding ecology in the western Arctic and offers regional, quantitative diet information that could support current and future food web modeling efforts.

  5. Abundance and distribution of Arctic cod (Boreogadus saida) and other pelagic fishes over the U.S. Continental Shelf of the Northern Bering and Chukchi Seas

    Science.gov (United States)

    De Robertis, Alex; Taylor, Kevin; Wilson, Christopher D.; Farley, Edward V.

    2017-01-01

    We conducted acoustic-trawl (AT) surveys of the northern Bering and Chukchi Seas during ice-free periods in 2012 and 2013. The mixed species assemblages in the study area required refinement of standard AT survey methods, and adjustment of trawl catches for the effects of trawl selectivity. Sensitivity analyses indicate that the AT abundance estimates are relatively robust to the assumptions of the analysis. These surveys indicate that midwater fishes are dominated by age-0 Arctic cod (Boreogadus saida), age-0 saffron cod (Eleginus gracilis), capelin (Mallotus villosus), and Pacific herring (Clupea pallasii). In both years, age-0 Arctic cod were distributed principally ≥69.5 °N, age-0 saffron cod were abundant in coastal areas between 66.5 and 69.5 °N, and Pacific herring were distributed south of 67 °N. These three fishes exhibited consistent associations with temperature, salinity and bottom depth: e.g., age-0 Arctic cod were abundant at lower mean water column temperatures than saffron cod. In contrast, capelin were distributed throughout the study area, and were not consistently associated with environmental measures. There was a geographic trend in body length, with smaller Arctic cod, saffron cod and capelin in northern areas, but smaller herring in the south. Arctic cod, saffron cod, herring and capelin were all >2 times more abundant in 2013 than 2012. Sizeable populations of age-0 Arctic cod were observed in the northern Chukchi Sea, which suggests that this area is an important nursery ground. However, relatively few older Arctic cod were observed in this and other surveys of the area, which suggests that either overwinter mortality of age-0 Arctic cod is high, and/or these fish are not retained on the Chukchi shelf.

  6. Coastal Environment, Bathymetry and Physical Oceanography along the Beaufort, Chukchi and Bering Seas.

    Science.gov (United States)

    1980-01-01

    fic 16 in th soute Shund.h A Sea reat a rdepth iemtr.Nmesrdct nortund along the Auasban shore wrist " a velt .f Here knt r rets rat ren veliy in caee 1...Area 6 Wave height/period PI. R-FC 12 --o.- . ........... 1 .- 2 C 0 S t 41 3%~ 0 -057 3io 0, Q; 0. . 1 X :’l NNN._ -. f " .~0 1 2 0. 0 .2 0 SLAC ME* 6

  7. Seasonal variation of CaCO3 saturation state in bottom water of a biological hotspot in the Chukchi Sea, Arctic Ocean

    Science.gov (United States)

    Yamamoto-Kawai, Michiyo; Mifune, Takahisa; Kikuchi, Takashi; Nishino, Shigeto

    2016-11-01

    Distribution of calcium carbonate saturation state (Ω) was observed in the Chukchi Sea in autumn 2012 and early summer 2013. Ω in bottom water ranged from 0.3 to 2.0 for aragonite and from 0.5 to 3.2 for calcite in 2012. In 2013, Ω in bottom water was 1.1-2.8 for aragonite and 1.7-4.4 for calcite. Aragonite and calcite undersaturation was found in high productivity regions in autumn 2012 but not in early summer 2013. Comparison with other parameters has indicated that biological processes - respiration and photosynthesis - are major factors controlling the regional and temporal variability of Ω. From these ship-based observations, we have obtained empirical equations to reconstruct Ω from temperature, salinity and apparent oxygen utilization. Using 2-year-round mooring data and these equations, we have reconstructed seasonal variation of Ω in bottom water in Hope Valley, a biological hotspot in the southern Chukchi Sea. Estimated Ω was high in spring and early summer, decreased in later summer, and remained relatively low in winter. Calculations indicated a possibility that bottom water could have been undersaturated for aragonite on an intermittent basis even in the pre-industrial period, and that anthropogenic CO2 has extended the period of aragonite undersaturation to more than 2-fold longer by now.

  8. Temperature, salinity, and sigma-t profiles from CTD casts from the Beaufort and Chukchi Seas from NOAA Ship OCEANOGRAPHER and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) the and Fisheries-Oceanography Cooperative Investigations (FOCI) from 1981-09-04 to 1987-09-16 (NODC Accession 9900072)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and sigma-t profiles were collected from CTD casts in the Beaufort and Chukchi Seas from NOAA Ship OCEANOGRAPHER and other platforms from 04...

  9. 楚科奇海的水螅水母类及其分布%THE HYDROMEDUSAE FROM CHUKCHI SEA AND ITS DISTRIBUTION

    Institute of Scientific and Technical Information of China (English)

    张金; 标林茂

    2000-01-01

    本文报道1999年7月至8月我国首次北极科学考察期间“雪龙”号破冰船在楚科奇海采 集的浮游水螅水母类及其分布。分析鉴定了8种水螅水母,其中4种属于花水母目.2种属于软 水母目,1种属于硬水母目,1种属于筐水母目。短新塔水母在楚科奇海是首次记录。简要记述了 这些种类的形态特征并附图。楚科奇海这8种水螅水母都是冷水种,其中6种为近岸性的,2种 是大洋性的。根据其地理分布可分为北极种、北极-北方种和北方寒温带种等3个类型,从动物 地理观点看,楚科奇海的水螅水母类应属于北极区系。楚科奇海水螅水母类的丰度一般较低,其 平均丰度为108个/100m3,水平分布状况主要由优势种所左右,八斑腕唇水母和指腺华丽水母 为优势种。垂直分层采样结果表明,指腺华丽水母分布于0~300m,其中以50~l00m居多。%The present paper is based on materials collected in Chukchi Sea during the period from July to August 1999 on icebreaker the R/V " Xuelong" by Chinese First Arctic Scientific Expedition. A total 8 species of pelagic Hydromedusae were identified, of which 4 species belonged to Anthomedusae, 2 species to Leptomedusae, 1 species to Trachymedusae and 1 species to Narcomedusae, the Neoturrls breviconis is recorded for the first time in Chukchi Sea. Their principal morphological characteristies are described and illustrated. The 8 species of Hydromedusae occurring in the Chukchi Sea all were cool water species, of which 6 species belong in neritic species, 2species in ocean species. According to the geographic distribution of species, they may be divided into three groups: Arctic species, Arctic-boreal species and Boreal-temperate species. From the view-point of zoogeography, species from these waters belong to the Arctic fauna. The abundance of Hydromedusae in Chukchi Sea was generally low, with a mean value of 108 ind

  10. Transport of trace metals (Mn, Fe, Ni, Zn and Cd) in the western Arctic Ocean (Chukchi Sea and Canada Basin) in late summer 2012

    Science.gov (United States)

    Kondo, Yoshiko; Obata, Hajime.; Hioki, Nanako; Ooki, Atsushi; Nishino, Shigeto; Kikuchi, Takashi; Kuma, Kenshi

    2016-10-01

    Distributions of trace metals (Mn, Fe, Ni, Zn and Cd) in the western Arctic Ocean (Chukchi Sea and Canada Basin) in September 2012 were investigated to elucidate the mechanisms behind the transport of these metals from the Chukchi Shelf to the Canada Basin. Filtered (melting sea-ice, influenced trace metal concentrations. The distribution patterns and concentration ranges were generally similar between the D and TD fractions for Ni, Zn and Cd, which indicate that Ni, Zn and Cd were present mainly in their dissolved forms, whereas the concentrations of TD-Fe and TD-Mn were generally higher than those of D-Fe and D-Mn, respectively. These results are consistent with the results of previous studies of this region. For both Fe and Mn, labile particulate (LP) concentrations (the difference between the TD and D fractions, which is acid-leachable fraction in the particles during storage at pH 1.5-1.6) were highest in the near-bottom waters of the Chukchi Shelf region. The relationships between the distance from the shelf break and the concentrations of trace metals revealed that Fe and Mn concentrations in halocline waters tended to decrease logarithmically with distance, whereas changes in the concentrations of Ni, Zn, Cd and phosphate with distance were small. These results suggest that the distributions of Fe and Mn were controlled mainly by input from shelf sediment and removal through scavenging processes. Based on the phase distributions of Fe and Mn, which were calculated as ratios between the LP and D fractions, different behaviors between Fe and Mn were expressed during lateral transportation. The concentration of TD-Fe declined rapidly via removal of LP-Fe from the water column, whereas the concentration of TD-Mn declined more slowly through the transformation of D-Mn into LP-Mn. In contrast, the concentrations of D-Cd, D-Zn and D-Ni were more strongly correlated with phosphate levels, which suggest that, like phosphate, the distributions of Cd, Zn and Ni were

  11. Chukchi Sea Bathymetry

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Bathymetric contours were generated from soundings collected during geophysical surveys conducted by the USGS from 1969 to 1982, and supplemented by data from other...

  12. Low 210Pb in the upper thermocline in the Canadian Basin:scavenge process over the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    HU Wangjiang; CHEN Min; YANG Weifeng; ZHANG Run; QIU Yusheng; ZHENG Minfang

    2014-01-01

    210Pb was measured during the 3rd Chinese National Arctic Research Expedition cruise to investigate its spa-tial pattern in the western Arctic Ocean, as well as its relation with the thermocline in the Canadian Basin. The specific activities varied from 0.04 to 2.72,<0.013 to 4.37, and 0.1 to 4.85 Bq/m3 for dissolved, particu-late, and bulk 210Pb, respectively, corresponding to respective averages of 0.65, 0.43, and 1.08 Bq/m3. In the Canadian Basin, the minimum 210Pb activities occurred in the thermocline, which was characterized by low temperature of-1.52°C and salinity of 33.1. Combining the spatial distribution of 210Pb and hydrographical characteristics in the western Arctic Ocean, this scenario was ascribed to the effective scavenging of 210Pb when the Pacific water flowed across the Chukchi Shelf. Quantitatively, this interpretation was supported by both the shorter residence times and higher scavenging efficiencies (SE) of dissolved 210Pb over the Chukchi Shelf. The highest SE values were observed in the Herald Shoal and bottom waters over the slope.

  13. Distribution, abundance, biomass and diversity of benthic infauna in the Northeast Chukchi Sea, Alaska: Relation to environmental variables and marine mammals

    Science.gov (United States)

    Schonberg, Susan V.; Clarke, Janet T.; Dunton, Kenneth H.

    2014-04-01

    In summer 2009 and 2010, as part of Chukchi Sea Offshore Monitoring in Drilling Area - Chemical and Benthos (COMIDA CAB) program, we performed a quantitative assessment of the biomass, abundance, and community structure of benthic infaunal populations of the Northeastern Chukchi Sea. This analysis documented a benthic species inventory of 361 taxa collected from 142 individual van Veen grab samples (0.1 m-2) at 52 stations. Infaunal abundance was dominated by Polychaeta, Mollusca, and Crustacea. Large concentrations of bivalves (up to 1235 m-2; 920.2 gww m-2) were collected south of Hanna Shoal where flow from two water masses converge and deposit labile carbon to the seafloor, as indicated by low surface sediment C:N ratios. Amphipods (up to 1640 m-2; 26.0 gww m-2), and polychaetes (up to 4665 m-2; 114.7 gww m-2) were documented from multiple stations west of and within Barrow Canyon. This high productivity was most likely due to the "canyon effect", where marine and coastal detrital carbon supplies are channeled by the canyon structure, enhancing carbon deposition and flux, which supports rich benthic communities within the canyon and surrounding areas. To examine the relationships between infaunal distributions of all collected taxa with the physical environment, we used a Biota and Environment matching (BIO-ENV) routine. A combination of water depth, bottom-water temperature and salinity, surface sediment total organic nitrogen (TON) and sediment C:N molar ratios correlated closest with infaunal abundance distribution (ρ=0.54), indicating that multiple factors influence the success of benthic communities. BIO-ENV routines produced similar correlation results when performed on targeted walrus prey items (bivalves (ρ=0.50), polychaetes (ρ=0.53), but gray whale prey items (amphipods) were not strongly correlated to any combination of physical environmental factors (ρ=0.24). Distributions of primary prey items for gray whales (amphipods) and walruses (bivalves

  14. Coupled Response of Bacterial Production to a Wind-induced Fall Phytoplankton Bloom and Sediment Resuspension in the Chukchi Sea Shelf, Western Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Mario Uchimiya

    2016-11-01

    Full Text Available Heterotrophic bacterial abundance and production, dissolved free amino acid (DFAA and dissolved combined amino acid (DCAA concentrations, and other microbial parameters were determined for seawater samples collected at a fixed station (maximum water depth, 56 m deployed on the Chukchi Sea Shelf, in the western Arctic Ocean, during a 16-day period in September 2013. During the investigation period, the sampling station experienced strong winds and a subsequent phytoplankton bloom, which was thought to be triggered by enhanced vertical mixing and upward nutrient fluxes. In this study, we investigated whether bacterial and dissolved amino acid parameters changed in response to these physical and biogeochemical events. Bacterial abundance and production in the upper layer increased with increasing chlorophyll a concentration, despite a concomitant decrease in seawater temperature from 3.2°C to 1.5°C. The percentage of bacteria with high nucleic acid content during the bloom was significantly higher than that during the prebloom period. The ratio of the depth-integrated (0–20 m bacterial production to primary production differed little between the prebloom and bloom period, with an overall average value of 0.14 ± 0.03 (± standard deviation, n = 8. DFAA and DCAA concentrations varied over a limited range throughout the investigation, indicating that the supply and consumption of labile dissolved amino acids were balanced. These results indicate that there was a tightly coupled, large flow of organic carbon from primary producers to heterotrophic bacteria during the fall bloom. Our data also revealed that bacterial production and abundance were high in the bottom nepheloid (low transmittance layer during strong wind events, which was associated with sediment resuspension due to turbulence near the seafloor. The impacts of fall wind events, which are predicted to become more prominent with the extension of the ice-free period, on bacterial

  15. Change in coccolith size and morphology due to response to temperature and salinity in coccolithophore Emiliania huxleyi (Haptophyta) isolated from the Bering and Chukchi seas

    Science.gov (United States)

    Saruwatari, Kazuko; Satoh, Manami; Harada, Naomi; Suzuki, Iwane; Shiraiwa, Yoshihiro

    2016-05-01

    Strains of the coccolithophore Emiliania huxleyi (Haptophyta) collected from the subarctic North Pacific and Arctic oceans in 2010 were established as clone cultures and have been maintained in the laboratory at 15 °C and 32 ‰ salinity. To study the physiological responses of coccolith formation to changes in temperature and salinity, growth experiments and morphometric investigations were performed on two strains, namely MR57N isolated from the northern Bering Sea and MR70N at the Chukchi Sea. This is the first report of a detailed morphometric and morphological investigation of Arctic Ocean coccolithophore strains. The specific growth rates at the logarithmic growth phases in both strains markedly increased as temperature was elevated from 5 to 20 °C, although coccolith productivity (estimated as the percentage of calcified cells) was similar at 10-20 % at all temperatures. On the other hand, the specific growth rate of MR70N was affected less by changes in salinity in the range 26-35 ‰, but the proportion of calcified cells decreased at high and low salinities. According to scanning electron microscopy (SEM) observations, coccolith morphotypes can be categorized into Type B/C on the basis of their biometrical parameters. The central area elements of coccoliths varied from thin lath type to well-calcified lath type when temperature was increased or salinity was decreased, and coccolith size decreased simultaneously. Coccolithophore cell size also decreased with increasing temperature, although the variation in cell size was slightly greater at the lower salinity level. This indicates that subarctic and arctic coccolithophore strains can survive in a wide range of seawater temperatures and at lower salinities with change in their morphology. Because all coccolith biometric parameters followed the scaling law, the decrease in coccolith size was caused simply by the reduced calcification. Taken together, our results suggest that calcification productivity may

  16. Marine mammal distribution and abundance in an offshore sub-region of the northeastern Chukchi Sea during the open-water season

    Science.gov (United States)

    Aerts, Lisanne A. M.; McFarland, Alexandra E.; Watts, Bridget H.; Lomac-MacNair, Kate S.; Seiser, Pamela E.; Wisdom, Sheyna S.; Kirk, Alex V.; Schudel, Carissa A.

    2013-09-01

    This paper describes the distribution and abundance of marine mammals during the open-water season within and near three offshore oil and gas prospects in the northeastern Chukchi Sea, known as the Klondike, Burger, and Statoil study areas. We collected vessel-based marine mammal data during July-October 2008-2010 along line transects oriented in a north-south direction. Over this period, we surveyed ~18,600 km of on-transect effort in the three study areas. Sightings of cetaceans were rare. The bowhead whale was the primary cetacean species sighted and was mostly observed in October (33 of 35 animals). Pinnipeds were the most abundant marine mammals in the study area, with 980 seals and 367 walruses recorded on transect. Most seals were observed as solitary animals, while walruses were often observed in aggregations. We calculated seal and walrus densities using species-specific detection functions corrected for probability of detection. There was high interannual variability in the abundance of seals and walruses that for some species may be related to interannual differences in ice conditions. Notwithstanding this variation, the distribution data suggest that benthic-feeding bearded seals and walruses generally were more common in the Burger and Statoil study areas, which can be characterized as more benthic-dominated ecosystems. The distribution of ringed/spotted seals did not show any statistically significant differences among the study areas, although a slight preference for the Klondike and Statoil study areas was suggested. Both of these study areas are affected by Bering Sea Water from the Central Channel and have a stronger pelagic component than the Burger study area. Continued sampling of these areas will help establish whether the observed trends in marine mammal distribution and abundance are persistent.

  17. Influence of timing of sea ice retreat on phytoplankton size during marginal ice zone bloom period in the Chukchi and Bering shelves

    Directory of Open Access Journals (Sweden)

    A. Fujiwara

    2015-08-01

    Full Text Available Timing of sea ice retreat (TSR as well as cell size of primary producers (i.e., phytoplankton plays crucial roles in seasonally ice-covered marine ecosystem. Thus, it is important to monitor the temporal and spatial distribution of phytoplankton community size structure. Prior to this study, an ocean color algorithm has been developed to derive phytoplankton size index FL, which is defined as the ratio of chlorophyll a derived from the cells larger than 5 μm to the total chl a using satellite remote sensing for the Chukchi and Bering shelves. Using this method, we analyzed pixel-by-pixel relationships between FL during marginal ice zone (MIZ bloom period and TSR over a period of 1998–2013. The influence of TSR on sea surface temperature (SST and changes in ocean heat content (ΔOHC during the MIZ bloom period were also investigated. A significant negative relationship between FL and TSR was widely found in the shelf region during MIZ bloom season. On the other hand, we found a significant positive (negative relationship between SST (ΔOHC and TSR. That is, earlier sea-ice retreat was associated with a dominance of larger phytoplankton during a colder and weakly stratified MIZ bloom season, suggesting that duration of nitrate supply, which is important for large-sized phytoplankton growth in this region (i.e., diatoms, can change according to TSR. In addition, under-ice phytoplankton blooms are likely to occur in years with late ice retreat, because sufficient light for phytoplankton growth can pass through the ice and penetrate into the water columns due to an increase in solar radiation toward the summer solstice. Moreover, we found not only the length of ice-free season but also annual median of FL positively correlated with annual net primary production (APP. Thus, both phytoplankton community composition and growing season are important for APP in the study area. Our findings showed quantitative relationship between the inter

  18. Influence of timing of sea ice retreat on phytoplankton size during marginal ice zone bloom period on the Chukchi and Bering shelves

    Science.gov (United States)

    Fujiwara, A.; Hirawake, T.; Suzuki, K.; Eisner, L.; Imai, I.; Nishino, S.; Kikuchi, T.; Saitoh, S.-I.

    2016-01-01

    The size structure and biomass of a phytoplankton community during the spring bloom period can affect the energy use of higher-trophic-level organisms through the predator-prey body size relationships. The timing of the sea ice retreat (TSR) also plays a crucial role in the seasonally ice-covered marine ecosystem, because it is tightly coupled with the timing of the spring bloom. Thus, it is important to monitor the temporal and spatial distributions of a phytoplankton community size structure. Prior to this study, an ocean colour algorithm was developed to derive phytoplankton size index FL, which is defined as the ratio of chlorophyll a (chl a) derived from cells larger than 5 µm to the total chl a, using satellite remote sensing for the Chukchi and Bering shelves. Using this method, we analysed the pixel-by-pixel relationships between FL during the marginal ice zone (MIZ) bloom period and TSR over the period of 1998-2013. The influences of the TSR on the sea surface temperature (SST) and changes in ocean heat content (ΔOHC) during the MIZ bloom period were also investigated. A significant negative relationship between FL and the TSR was widely found in the shelf region during the MIZ bloom season. However, we found a significant positive (negative) relationship between the SST (ΔOHC) and TSR. Specifically, an earlier sea ice retreat was associated with the dominance of larger phytoplankton during a colder and weakly stratified MIZ bloom season, suggesting that the duration of the nitrate supply, which is important for the growth of large-sized phytoplankton in this region (i.e. diatoms), can change according to the TSR. In addition, under-ice phytoplankton blooms are likely to occur in years with late ice retreat, because sufficient light for phytoplankton growth can pass through the ice and penetrate into the water columns as a result of an increase in solar radiation toward the summer solstice. Moreover, we found that both the length of the ice-free season

  19. Change in coccolith morphology by responding to temperature and salinity in coccolithophore Emiliania huxleyi (Haptophyta) isolated from the Bering and Chukchi Seas

    Science.gov (United States)

    Saruwatari, K.; Satoh, M.; Harada, N.; Suzuki, I.; Shiraiwa, Y.

    2015-11-01

    Strains of the coccolithophore Emiliania huxleyi (Haptophyta) collected from the subarctic North Pacific and Arctic Oceans during the R/V MIRAI cruise in 2010 (MR10-05) were established as clone cultures and have been maintained in the laboratory at 15 °C and 32 ‰ salinity. To study the physiological responses of coccolith formation to changes in temperature and salinity, growth experiments and morphometric investigations were performed on two strains of MR57N isolated from the northern Bering Sea (56°58' N, 167°11' W) and MR70N at the Chukchi Sea (69°99' N, 168° W). This is the first report of a detailed morphometric and morphological investigation of Arctic Ocean coccolithophore strains. The specific growth rates at the logarithmic growth phases in both strains markedly increased as temperature was elevated from 5 to 20 °C, although coccolith productivity (the percentage of calcified cells) was similar at 10-20 % at all temperatures. On the other hand, the specific growth rate of strain MR70N was affected less by changes in salinity in the range 26-35 ‰, but the proportion of calcified cells decreased at high and low salinities. According to scanning electron microscopy (SEM) observations, coccolith morphotypes can be categorized into Type B/C on the basis of their biometrical parameters, such as length of the distal shield (LDS), length of the inner central area (LICA), and the thickness of distal shield elements. The central area elements of coccoliths varied from grilled type to closed type when temperature was increased or salinity was decreased, and coccolith size decreased simultaneously. Coccolithophore cell size also decreased with increasing temperature, although the variation in cell size was slightly greater at the lower salinity level. This indicates that subarctic and arctic coccolithophore strains can survive in a wide range of seawater temperatures and at lower salinities due to their marked morphometric adaptation ability. Because all

  20. Distribution, Abundance, Behavior, and Bioacoustics of Endangered Whales in the Western Beaufort and Northeastern Chukchi Seas, 1979-87

    Science.gov (United States)

    1988-07-01

    the area. Other Marine Mammals a. Belukha or White Whale ( Delphinapterus leucas ) Thirty-three sightings of 140 belukhas were made in the western...contour was clipped near St . Lawrence Island in the Bering Sea. Data Processing and Quality Control A computer program (SPEED) was written to screen for...Estimates 42 c. Habitat Relationships and Behavior 43 d. Calf Sightings 44 ix Page Other Marine Mammals 44 a. Belukha, or White Whale ( Delphinapterus

  1. 楚科奇海和白令海的海洋低温微生物调查%THE SURVEY OF MARINE MICROORGANISMS IN LOW TEMPERATURES OF CHUKCHI AND BERING SEA

    Institute of Scientific and Technical Information of China (English)

    曾胤新; 陈波; 蔡明红; 何剑锋

    2001-01-01

    Investigations of total number of marine microbes in low temperatures of Chukchi Sea and Bering sea were conducted during the summer time in north hemisphere. In Chukchi Sea the detection rates of marine bacteria and fungi were 100% and more than 94%, respectively. And the quantity of marine bacteria generally was more than 103 cells/cm3, and that of marine fungi usually 10-103 cells/cm3. In most investigation sites marine bacterial total numbers were higher than marine fungal total numbers. There are abundant marine microorganisms distributing in the areas from surface water to deeper layers of 10m or 30m depth in Chukchi Sea. Results showed that there were large differences of marine microbial total numbers between different sampling sites, and the melt sea ice and salinity in sea water were probably two important factors affecting the marine microbial amounts in Chukchi Sea. As to marine bacteria in Bering sea, their detection rates were 100% and their amounts were generally 102—103 cells/cm3. For marine fungi, their detection rates were more than 84% and their amounts generally 102-103 cells/cm3. Similar to the situation in Chukchi Sea, there were fairly large differences of marine microbial total numbers between different sampling sites in Bering Sea, too.The investigation results proved that a large number of marine microbes in low temperatures lived in Chukchi and Bering Sea. Among the marine bacteria studied, 81% of bacteria from Chukchi Sea and 88.9% of bacteria from Bering sea can grow well in low temperatures no higher than 10℃. And some of these marine bacteria can utilize starch or cellulose as carbon source for their growth. These microbes can provide abundant materials for further exploiting and developing the marine microbe resources in low temperature.%在1999年北极夏季期间对楚科奇海和白令海的海洋低温微生物进行了调查。在楚科奇海,海洋细菌和海洋真菌的检出率分别为100%和>94%,其相

  2. Short-term changes in the mesozooplankton community and copepod gut pigment in the Chukchi Sea in autumn: reflections of a strong wind event

    Science.gov (United States)

    Matsuno, K.; Yamaguchi, A.; Nishino, S.; Inoue, J.; Kikuchi, T.

    2015-07-01

    To evaluate the effect of atmospheric turbulence on a marine ecosystem, high-frequency samplings (two to four times per day) of a mesozooplankton community and the gut pigment of dominant copepods were performed at a fixed station in the Chukchi Sea from 10 to 25 September 2013. During the study period, a strong wind event (SWE) was observed on 18 September. After the SWE, the biomass of chlorophyll a (Chl a) increased, especially for micro-size (> 10 μm) fractions. The zooplankton abundance ranged from 23 610 to 56 809 ind. m-2 and exhibited no clear changes as a result of the SWE. In terms of abundance, calanoid copepods constituted the dominant taxa (mean: 57 %), followed by barnacle larvae (31 %). Within the calanoid copepods, small-sized Pseudocalanus spp. (65 %) and large-sized C. glacialis (30 %) dominated. In the population structure of C. glacialis, copepodid stage 5 (C5) dominated, and the mean copepodid stage did not vary with the SWE. The dominance of accumulated lipids in C5 and C6 females with immature gonads indicated that they were preparing for seasonal diapause. The gut pigment of C. glacialis C5 was higher at night and was correlated with ambient Chl a (Chl a, and a significant increase was observed after the SWE (2.6 vs. 4.5 ng pigment ind.-1). The grazing impact by C. glacialis C5 was estimated to be 4.14 mg C m-2 day-1, which corresponded to 0.5-4.6 % of the biomass of the micro-size phytoplankton. Compared with the metabolic food requirement, C. glacialis feeding on phytoplankton accounted for 12.6 % of their total food requirement. These facts suggest that C. glacialis could not maintain their population by feeding solely on phytoplankton and that other food sources (i.e., microzooplankton) must be important in autumn. As observed by the increase in gut pigment, the temporal phytoplankton bloom, which is enhanced by the atmospheric turbulence (SWE) in autumn, may have a positive effect on copepod nutrition.

  3. Estimating Arctic sea-ice freeze-up and break-up from the satellite record: A comparison of different approaches in the Chukchi and Beaufort Seas

    OpenAIRE

    Mark Johnson; Hajo Eicken

    2016-01-01

    1. Abstract The recognized importance of the annual cycle of sea ice in the Arctic to heat budgets, human behavior, and ecosystem functions, requires consistent definitions of such key events in the ice cycle as break-up and freeze-up. An internally consistent and reproducible approach to characterize the timing of these events in the annual sea-ice cycle is described. An algorithm was developed to calculate the start and end dates of freeze-up and break-up and applied to time series of satel...

  4. A comparison of ringed and bearded seal diet, condition and productivity between historical (1975-1984) and recent (2003-2012) periods in the Alaskan Bering and Chukchi seas

    Science.gov (United States)

    Crawford, Justin A.; Quakenbush, Lori T.; Citta, John J.

    2015-08-01

    Reductions in summer sea ice in the Chukchi and Beaufort seas are expected to affect what has been an ice-adapted marine food web in the Pacific Arctic. To determine whether recent decreases in sea ice have affected ice-associated marine predators (i.e., ringed, Pusa hispida, and bearded seals, Erignathus barbatus) in the Bering and Chukchi seas we compared diet, body condition, growth, productivity, and the proportion of pups harvested (an index of weaning success) for seals of each species harvested by 11 Alaskan villages during two periods; a historical (1975-1984) and a recent period (2003-2012). We also examined how changes in indices of seal health may be correlated with the reduction of sea ice characteristic of the recent period. For ringed seals ⩾1 year of age, the % frequency of occurrence (%FO) of Arctic cod (Boreogadus saida), walleye pollock (Gadus chalcogramma), rainbow smelt (Osmerus mordax), and Pacific herring (Clupea pallasi) increased from the historic to the recent period, while the %FO of invertebrates decreased for both pups and seals ⩾1 year of age. For bearded seals ⩾1 year of age, the %FO of Arctic cod, pricklebacks, and flatfish increased during the recent period, while the %FO of saffron cod (Eleginus gracilis) decreased for pups. Although invertebrates did not change overall for either age class, decreases occurred in 10 of 24 specific prey categories, for bearded seals ⩾1 year of age; only echiurids increased. The %FO of gastropods and bivalves increased for pups while isopods and one species of shrimp and crab decreased in occurrence. During the recent period ringed seals grew faster, had thicker blubber, had no change in pregnancy rate, matured 2 years earlier, and a larger proportion of pups was harvested than during the historical period. Correlations with spring ice concentration showed that the growth and blubber thickness of seals ⩾1 year of age, blubber thickness of pups, and the proportion of pups in the harvest all

  5. Retrieval of Melt Ponds on Arctic Multiyear Sea Ice in Summer from TerraSAR-X Dual-Polarization Data Using Machine Learning Approaches: A Case Study in the Chukchi Sea with Mid-Incidence Angle Data

    Directory of Open Access Journals (Sweden)

    Hyangsun Han

    2016-01-01

    Full Text Available Melt ponds, a common feature on Arctic sea ice, absorb most of the incoming solar radiation and have a large effect on the melting rate of sea ice, which significantly influences climate change. Therefore, it is very important to monitor melt ponds in order to better understand the sea ice-climate interaction. In this study, melt pond retrieval models were developed using the TerraSAR-X dual-polarization synthetic aperture radar (SAR data with mid-incidence angle obtained in a summer multiyear sea ice area in the Chukchi Sea, the Western Arctic, based on two rule-based machine learning approaches—decision trees (DT and random forest (RF—in order to derive melt pond statistics at high spatial resolution and to identify key polarimetric parameters for melt pond detection. Melt ponds, sea ice and open water were delineated from the airborne SAR images (0.3-m resolution, which were used as a reference dataset. A total of eight polarimetric parameters (HH and VV backscattering coefficients, co-polarization ratio, co-polarization phase difference, co-polarization correlation coefficient, alpha angle, entropy and anisotropy were derived from the TerraSAR-X dual-polarization data and then used as input variables for the machine learning models. The DT and RF models could not effectively discriminate melt ponds from open water when using only the polarimetric parameters. This is because melt ponds showed similar polarimetric signatures to open water. The average and standard deviation of the polarimetric parameters based on a 15 × 15 pixel window were supplemented to the input variables in order to consider the difference between the spatial texture of melt ponds and open water. Both the DT and RF models using the polarimetric parameters and their texture features produced improved performance for the retrieval of melt ponds, and RF was superior to DT. The HH backscattering coefficient was identified as the variable contributing the most, and its

  6. Temperature and other data were collected using thermometer and bottle casts in the Chukchi and Bering Sea from 1947-02-11 to 1949-07-26 (NODC Accession 9700081)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, depth, oxygen, and salinity data were collected using thermometer and bottle casts from the USS CACOPAN, USS NEREUS, and HMCS CEDARWOOD in the Chukchi...

  7. Primary Production and C Flow in the Chukchi Sea Land-Fast Ice-Ocean Ecosystem and Sensitivity to Environmental Factors

    Science.gov (United States)

    Deal, C. J.; Jin, M.; Wang, J.; Whitledge, T. E.; Lee, S. H.

    2005-12-01

    The recent downward trend in Arctic sea ice extent and thickness is a compelling indicator of climate change. These changes in sea ice affect the arctic marine ecosystem, which may depend on sea ice algal primary production for over 50% of the fixed C in the permanently ice-covered Arctic (Gosselin et al., 1997) and up to 25% in the surrounding marginal seas (Kirst and Wiencke, 1995). Since land-fast ice is generally the most accessible of the four sea ice regimes (perennial pack ice, coastal zone - including fast ice, seasonal pack ice and marginal ice zone), and in its own right is important in terms of aereal extent, on-going environmental changes along the coast and a platform for significant biological activity, our research group has focused on time series observations in the land-fast ice near Barrow, Alaska over the last several years. We have utilized the resultant data and those available from other research groups to develop a 1-D marine ecosystem model from which we have constructed an organic C budget based on observations including ice algal biomass (chl a), phytoplankton biomass (chl a), POC, PON, indicators of zooplankton and ice meiofaunal grazing, nutrients, in situ carbon and nutrient uptake, temperature, salinity, ice thickness and snow cover. Through model sensitivity studies, we found that doubling of the initial nutrient concentrations has a significant impact on sea ice primary production, being roughly proportional. Also, a doubling of light (PAR) shifts the exponential accumulation of sea ice algal biomass ahead approximately one week. These model results provide evidence that changes in river discharge that alter nutrient concentrations, and changes in the light regime linked to ongoing environmental changes such as sediment loading, lessening sea ice thickness, and interannual variations in snow cover significantly impact the marine ecosystem. These influences may cascade through the marine ecosystem to affect the food web and hence

  8. Aerial Surveys of Endangered Whales in the Northern Bering, Eastern Chukchi, and Alaskan Beaufort Seas, 1984: with a Six Year Review, 1979-1984.

    Science.gov (United States)

    1985-06-01

    Scheidt supplied satellite imagery from the National Weather Service, U. S. Department of Commerce. Jeanne Cole and Barbara McAvoy of SEACO, Inc. typed...70048.6’ 1 0015.2’ 562 MP FE 300 0 B4 22 A-42 Il * -0- CHUIKCHI SEA 72 PT BA 71 CAPEIC CAPER ~ 1370 LEEN A-43 Flight 21: 30 July 1994 Flight was a

  9. SPATIAL DISTRIBUTION OF PICO-AND NANO-PHYTOPLANKTON AND BACTERIA IN THE CHUKCHI SEA WITH RELATION TO WATER MASSES%夏季北冰洋楚科奇海微微型、微型浮游植物和细菌的丰度分布特征及其与水团的关系

    Institute of Scientific and Technical Information of China (English)

    张芳; 何剑锋; 郭超颖; 林凌; 马玉欣

    2012-01-01

    Based on the third Chinese Arctic Expedition cruise in the summer of 2008, the distribution patterns of pico-and nano-plankton and bacterial abundances were studied in the Chukchi Sea. Pico- and nano-phytoplankton abundances ranged from 0. 01×103 to 5. 51×103 cells·mL-1 and from 0.01×103 to 5. 51×103 cells·mL-1, respectively. The lowest numbers of bacteria in the entire water column were recorded at station R17 at 100 m depth (0. 21×106 cells·mL-1) , and the highest concentration was observed at station R09 at 10 m depth (9. 61×106 cells·mL-1). Our results demonstrate that melting sea ice affects the physical characteristics of the Chukchi Sea by reducing the salinity of the surface mixed layer which, in turn, results in greater hydrodynamic stability of the water column. These changes were accompanied by increasing bacterial concentrations. Pacific warm water brought high nutrient concentrations into the Chukchi Sea, which led to higher abundances of bacteria and nano-phytoplank-ton compared to other regions of the Arctic Ocean. However, the number of pico-phytoplankton in the Anadyr Water related well to chlorophyll a, and the number was greater than those in the other two water masses. The structure of pico- and nano-plankton communities, coupled with the water masses in the Chukchi Sea, can be considered indicators of the inflow of Pacific warm water into the Chukchi Sea.%利用2008年中国第三次北极科学考察的机会,分析夏季楚科奇海微微型、微型浮游植物和细菌丰度的分布特征,并探讨它们与楚科奇海水团之间的关系.结果表明:与北冰洋的其他海域相比,楚科奇海的微型浮游植物丰度相对较高(0.03-10.23×103 cells·mL-1),微微型浮游植物则大致相同(0.01-2.21×103 cells·mL-1),而浮游细菌丰度明显较高(0.21-9.61×106 cells·mL-1).白令海陆架水与海冰融化混合水和阿纳德尔水浮游植物群落结构不同,夏季随着太平洋水入流水对楚科奇海

  10. Aerial Surveys of Endangered Whales in the Northern Bering, Eastern Chukchi, and Alaskan Beaufort Seas, 1985: With a Seven Year Review, 1979-85.

    Science.gov (United States)

    1986-08-01

    8217 . " - • " " " ’ " ’"" . - - - " "" "° " " "" " " , , - " UUSS USSRA as LEGENDJ 0GV S CAPE PRINCE OF WALES % .4(DO crnM BERING SEA OCG 00 M 0a hI)rO 0 0 0 1 Kp 000...o,,o_.._ .- Demarcation Pt Cape Lisbuneo 680I , ialn 680: 660 USSR16 100 15 1 apatocni Prince of Wales AndSK i nest coe s dNo o i 64...and migration patterns of the white whale ( Beluga ), Delphinapterus leucas. Rep. int. Whal. Commn. vol. 30:465-480. 1980. Herzing, D.L. and B.R. Mate

  11. THE COMPOSITION AND SOURCES OF SUSPEND ED PARTICLES OF IN THE CHUKCHI SEA AND THE CENTRAL ARCTIC OCEAN%楚科奇海表层海水颗粒物组成与来源

    Institute of Scientific and Technical Information of China (English)

    于晓果; 雷吉江; 姚旭莹; 朱继浩; 金肖兵

    2014-01-01

    对研究区内第五次北极科学考察所取的表层海水颗粒物的浓度、显微组成、有机碳、氮含量及其同位素组成进行了分析。结果表明,楚科奇海域表层海水颗粒物浓度介于0.56-4.01 mg·L-1,具有冰区边缘高于开阔水域的特点。陆架区颗粒有机质相对含量高(TOC:9.78%-20.24%;TN:0.91%-2.31%),有机碳、氮同位素值相对重(δ13 C:-23.29‰--26.33‰ PDB;δ15 N:6.14‰-7.78‰),有机质主要来源于海洋生物,含有部分陆源有机质;陆坡及北冰洋核心区的颗粒有机质含量,除SR15站外,相对低(TOC:8.06%-8.96%;TN:0.46%-0.72%),有机碳、氮同位素值轻(δ13 C:-26.93‰--27.78‰ PDB;δ15 N:4.13‰-4.84‰),颗粒物有机质以陆源为主。陆坡区SR15站表层海水颗粒物中异常高的陆源有机质(TOC:27.94%,TN:1.16%;δ13C:-27.43;δ15N:3.81)可能来自源于东西伯利亚的穿极洋流。海冰携带的颗粒物(包括冰藻)是冰区边缘表层海水颗粒物的重要来源,在陆架区海冰融化,向水体中释放了大量生物体;而陆坡区和北冰洋核心区,海冰对颗粒物的贡献以碎屑矿物和黏土矿物为主。%Suspended particle samples were collected at 1 1 stations in the shelf and slope regions of the Chukchi Sea and the central Arctic Ocean during the Fifth Chinese Arctic Research Expedition in the summer 2012.The particle concentrations,TOC,TN and the carbon and nitrogen isotopic compositions of the samples were analyzed.The concentration of suspended particles is between 0.56 mg·L-1 and 4.01 mg·L-1 ,with the samples collected from the edge area of the sea ice having higher concentrations.The content of organic matter is higher in the shelf area (TOC:9.78%-20.24%;TN:0.91%-2.31%),and with heavier isotopic compositions (δ13C:-23.29‰--26.33‰;δ15 N:6.14‰-7.78

  12. 白令海和楚科奇海鱼类种类组成及其对生态环境变化的响应%Composition of fish species in Bering Sea and Chukchi Sea and its responses to changes of ecological environment

    Institute of Scientific and Technical Information of China (English)

    陈永俊; 林龙山; 廖运志; 张静; 宋普庆; 余兴光; 吴日升; 邵广昭

    2013-01-01

    根据第4次中国北极科学考察在白令海与楚科奇海进行的鱼类拖网调查资料,分析了白令海与楚科奇海鱼类生物的种类组成、优势种、物种多样性和区系特征,探讨了鱼类生物对北极气候快速变化的响应.结果表明,白令海与楚科奇海两个海域共鉴定鱼类生物14科41种;主要优势种类为粗壮拟庸鲽(Hippoglossoides robustus)、北鳕(Boreogadus saida)、短角床杜父鱼(Myoxocephalus scorpius)、斑鳍北鳚(Lumpenus abricii)、粗糙钩杜父鱼(Artediellus scaber);从适温性来看,冷水性种类最多,有35种,冷温性种类6种;从栖息地生态类型来看,底层鱼类、近底层鱼类和中上层鱼类分别为35、5和1种;Shannon-Wiener多样性指数平均为1.21,呈现南高北低的特点,整体多样性水平不高;气候变化引起部分北极、亚北极海区鱼类出现不同程度的纬向和纵向移动,由此将引起北极渔业资源分布格局的变化.%On the basis of trawl surveys in the Bering Sea and Chukchi Sea during the 2010 Chinese Arctic Research Expedition, the fish biodiversity feature, such as fish species composition, dominant species, biodiversity and fau-nal characteristics were conducted. We discussed the responses of fishes due to the quick changes of Arctic climate. The results show that a total of 41 species in 14 families have been recorded in Bering Sea and Chukchi Sea. The dominant species are Hippoglossoides robustus, Boreogadus saida, Myoxocephalus scorpius, Lumpenus fabricii, Artediellus scaber. There are 35 cold water species and 6 cold temperate species. The habitat types of fish can be grouped as follows: 35 demersal fishes, 5 benthopelagic fishes, and 1 pelagic fish, respectively. Shannon—Wiener diversity index(H')(range between 0 and 2. 18, and 1. 21 in average) was not high, descend from south to north. Climate change has urged some fishes to shift in their latitudinal and longitudinal distribution around the

  13. Sedimentary input of trace metals from the Chukchi Shelf

    Science.gov (United States)

    Aguilar-Islas, A. M.; Seguré, M.; Rember, R.; Nishino, S.

    2014-12-01

    The distribution of trace metals in the Arctic Ocean has implications for their global cycles, yet until recently few trace metal observations were available from this rapidly changing ocean. Profiles of dissolved Fe from recent Japanese field efforts in the Western Canada Basin (2008, 2010) indicate the broad Chukchi Shelf as a source of Fe to the halocline of the Western Canada Basin. Here we present dissolved and particulate data for crustal (Al, Mn, Fe) and non-crustal elements (Co, Cu, Zn) from the productive Chukchi Sea to characterize the sedimentary input of these metals to shelf waters contributing to the halocline layer of the Canada Basin. Water column profiles were collected in late summer 2013 onboard the R/V Mirai at 10 stations from the Bering Strait to the slope, and at a time-series (10 days) station located over the outer shelf. A narrow and variable (5-10 m) benthic boundary layer was sampled at the time-series station with highly elevated dissolved and suspended particulate metal concentrations. High metal concentrations were also observed in the subsurface at a station over Barrow Canyon where mixing is enhanced. Reactivity of suspended particulate metals was determined by the leachable vs. refractory fractions. Metal concentrations were determined by ICP-MS. Trace metal transport from the shelf to the interior will be discussed in context with shelf mechanisms contributing to this export, and to expected future changes in the Arctic Ocean.

  14. Atmospheric Profiles, Clouds, and the Evolution of Sea Ice Cover in the Beaufort and Chukchi Seas: Atmospheric Observations and Modeling as Part of the SeasonalIce Zone Reconnaissance Surveys

    Science.gov (United States)

    2015-09-30

    ability of global atmospheric reanalyses and forecast models to reflect the details of the seasonal evolution of atmosphere- ice -ocean interactions in the...analog for expected future ice retreat. SIZRS takes advantage of routine Coast Guard C-130 domain awareness missions that take place at bi-weekly...radiative processes might be more important for the underlying sea ice . Under synoptic condition S04, the warm , dry, and strongly stratified atmosphere

  15. [Comparative analysis of sea-ice diatom species composition in the seas of Russian Arctic].

    Science.gov (United States)

    Il'iash, L V; Zhitina, L S

    2009-01-01

    Comparative analysis of species composition of ice diatom algae (IDA) of the White, Barents, Kara, Laptev, East Siberian, Chukchi Seas and the Basin of the Arctic Ocean was conducted on the basis of both original and published data. Species composition of IDA counts 567 taxa including 122 centric and 446 pennate diatoms. The freshwater algae composed about 18% of the total species number. In the White Sea, IDA were the most numerous (272 taxa), in the Kara Sea they are the least numerous (57 taxa). The species compositions in different seas differ significantly from each other. Similarity of IDA was consistent with the Arctic Ocean circulation and ice drift. IDA of Chukchi, East Siberian and Laptev Seas are the most similar, as are IDA of White and Kara Seas. Similarity of IDA of Chukchi Sea to those of other seas decrease in the west direction. IDA species differences between regions within one sea could be greater than those between different seas.

  16. Rapid and significant temperature changes at the near bottom of central Chukchi Sea in summer 2008%2008年夏季楚科奇陆架海域近底层水温大幅快速变化事件研究

    Institute of Scientific and Technical Information of China (English)

    舒启; 乔方利; 陈红霞

    2012-01-01

    2008年夏季中国第3次北极科学考察期间,利用锚碇潜标对北冰洋楚科奇陆架海域进行了为期33 d的海流剖面、近底层温度与盐度连续观测.观测数据显示楚科奇陆架海域近底层海水温度出现了两次较大幅度的快速升降现象.结合此次科学考察R断面温盐深仪(CTD)观测资料、以及卫星遥感海表温度(SST)和海表风场等资料,综合分析表明:观测到的这种快速升、降温现象不仅发生在近底层;这种快速升、降温现象应该是由海水温度锋面在夏季整体缓慢北移的同时存在短暂南北摆动所导致;温度锋面的季节性北移属于北极气候特征,而温度锋面短暂的南北摆动则与短期天气过程有关.%During the third CHINARE Arctic Expedition in summer 2008, 33 days of current profile, near bottom sea water temperature and salinity data in central Chukchi Sea were collected by a mooring system (CN-1). The observed data shows that near bottom water temperature has two rapid and significant chan-ges during the observation. CTD (Conductivity Temperature Depth) data along R-section collected in this expedition, NOAA (National Oceanic and Atmospheric Administration) AVHRR (Advanced Very High Resolution Radiometer) SST (Sea Surface Temperature) and NOAA sea surface wind data are used to analyze the rapid and significant temperature changes. The results showed that water temperature changes rapidly at not only the bottom layer but also the upper layer. The rapid temperature changes are caused by the movement of temperature front. The movement consists of two parts, northward movement and swing in the direction of north-south. The northward movement is related to climate characteristics, and the swing is related to synoptic characteristics.

  17. Individual animals and other data collected using visual observations and other instruments from AIRCRAFT in the Bering Sea and other seas from 02 September 1990 to 07 November 1991 (NODC Accession 9200080)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Individual Animal and other data were collected using visual observation and other instruments from AIRCRAFT in the Bering Sea, Chukchi Sea, and Arctic Ocean. Data...

  18. Distribution of Pacific-origin water in the region of the Chukchi Plateau in the Arctic Ocean in the summer of 2003

    Institute of Scientific and Technical Information of China (English)

    SHI Jiuxin; CAO Yong; ZHAO Jinping; GAO Guoping; JIAO Yutian; LI Shujiang

    2005-01-01

    The upper ocean thermohaline structures in the region of the Chukchi Plateau are analyzed with the hydrographic data collected by the Chinese National Arctic Research Expedition in the summer of 2003. Three types of the Pacific-origin water were found in the upper ocean, Alaska Coastal Water (ACW), summer Bering Sea Water (sBSW) and winter Bering Sea Water (wBSW) are indicated by two maximums temperature and one minimum temperature, piling up from the upper to the lower respectively. The extreme warm ACW with a maximum temperature of 1.62 ℃ was found in the southwestern Canada Basin at a depth of about 50 m. A pathway of the ACW into the basin from its adjacent area did not existed in the expedition period. So it is speculated that the extreme warm feature of the ACW was formed locally in 2003. The relative weak ACW occurred to the east of the Chukchi Cap and in the southern Chukchi Abyssal Plain. The latter one might originate from a warm downwelling that existed in a small canyon at the shelf break of the Chukchi Sea. The sBSW without the ACW was found only at the southwestern flank of the Chukchi Cap. The ACW and the sBSW were not found in the northernmost station at 81°N,which indicates the north boundary of the upper Pacific-origin water in the Canada Basin. The wBSW, which existed in all deep stations, was exactly uniform at temperature. The difference of the core potential temperature of the wBSW in the deep regions is only 0.08 ℃.

  19. Sunlight, Sea Ice, and the Ice Albedo Feedback in a Changing Arctic Sea Ice Cover

    Science.gov (United States)

    2015-09-30

    the Arctic Ocean and surrounding seas, with particular emphasis on the Chukchi and Beaufort Seas. Some of the largest changes to the sea ice cover are...Changing Arctic Sea Ice Cover Don Perovich ERDC – CRREL 72 Lyme Road Hanover, NH 03755 Phone: 603-646-4255 Email: donald.k.perovich...quantitative understanding of the partitioning of solar radiation by the Arctic sea ice cover and its impact on the heat and mass balance of the ice and upper

  20. Warming in Arctic intermediate and deep waters around Chukchi Plateau and its adjacent regions in 1999

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Jinping; GAO; Guoping

    2005-01-01

    Based on the data measured during Arctic scientific expedition of China in 1999, the characteristics of temperature and salinity distributions around the Chukchi Plateau and its adjacent regions have been studied. It was found that the intermediate water with temperature higher than 0.5℃ existed in all parts of a 640 km section with a maximum temperature of 0.85℃ indicating a strong signal of the warming in Arctic Intermediate Water in 1999. Two important phenomena are described in this paper. First, the temperature of warm water was horizontally nonuniform. In the area of Chukchi Plateau, the temperature was higher, the layer of warm water was thicker and the depth of the warm water core was shallower than those in the area of continental slope. The horizontal nonuniformity of the temperature distribution of warming water implies that the upward heat flux should also be nonuniform, thus exerting different effects on sea ice thickness, ice extent, and air-sea heat exchange. The mechanism to generate higher temperature in the plateau region was the bypassing of current around the plateau area caused by the special local topography, which restricted water exchange across the plateau and conserved heat in the water body. Second, the deep water down to 1400 m was also warming with a temperature increase of 0.2℃. The warming in deep water reflects the occurrence of complicated heat redistribution processes in the intermediate water, which altered the thermal structure in the upper 1400 m. The warming data embody the obvious impact of global climate change on the Arctic Ocean and further studies are wanted.

  1. Decadal shifts in autumn migration timing by Pacific Arctic beluga whales are related to delayed annual sea ice formation.

    Science.gov (United States)

    Hauser, Donna D W; Laidre, Kristin L; Stafford, Kathleen M; Stern, Harry L; Suydam, Robert S; Richard, Pierre R

    2016-12-21

    Migrations are often influenced by seasonal environmental gradients that are increasingly being altered by climate change. The consequences of rapid changes in Arctic sea ice have the potential to affect migrations of a number of marine species whose timing is temporally matched to seasonal sea ice cover. This topic has not been investigated for Pacific Arctic beluga whales (Delphinapterus leucas) that follow matrilineally maintained autumn migrations in the waters around Alaska and Russia. For the sympatric Eastern Chukchi Sea ('Chukchi') and Eastern Beaufort Sea ('Beaufort') beluga populations, we examined changes in autumn migration timing as related to delayed regional sea ice freeze-up since the 1990s, using two independent data sources (satellite telemetry data and passive acoustics) for both populations. We compared dates of migration between 'early' (1993-2002) and 'late' (2004-2012) tagging periods. During the late tagging period, Chukchi belugas had significantly delayed migrations (by 2 to >4 weeks, depending on location) from the Beaufort and Chukchi seas. Spatial analyses also revealed that departure from Beaufort Sea foraging regions by Chukchi whales was postponed in the late period. Chukchi beluga autumn migration timing occurred significantly later as regional sea ice freeze-up timing became later in the Beaufort, Chukchi, and Bering seas. In contrast, Beaufort belugas did not shift migration timing between periods, nor was migration timing related to freeze-up timing, other than for southward migration at the Bering Strait. Passive acoustic data from 2008 to 2014 provided independent and supplementary support for delayed migration from the Beaufort Sea (4 day yr(-1) ) by Chukchi belugas. Here, we report the first phenological study examining beluga whale migrations within the context of their rapidly transforming Pacific Arctic ecosystem, suggesting flexible responses that may enable their persistence yet also complicate predictions of how

  2. Sunlight, Sea Ice, and the Ice Albedo Feedback in a Changing Artic Sea Ice Cover

    Science.gov (United States)

    2015-11-30

    Arctic sea ice cover and its impact on the heat and mass balance of the ice and upper ocean ... Arctic Ocean and surrounding seas, with particular emphasis on the Chukchi and Beaufort Seas. Some of the largest changes to the sea ice cover are...other parts of the Arctic ice cover appear to now be accelerating. Figure 6. Maps of the linear trend of annual solar heat input to the ocean

  3. Current measurements collected at three moorings deployed across the Chukchi continental slope west of the Chukchi Rise in the Chukchi Borderland region to measure the Arctic Ocean boundary current, August - September 2002 (NODC Accession 0002693)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 35-day NSF-sponsored cruise aboard the USCGC Polar Star has studied in depth the physical oceanography of the Chukchi Borderland and Mendeleev Ridge regions. An...

  4. Recent Mapping and Sampling on Chukchi Borderland and the Alpha/Mendeleev Ridge Complex

    Science.gov (United States)

    Mayer, L. A.; Brumley, K.; Andronikov, A.; Chayes, D. N.; Armstrong, A. A.; Calder, B.; Hall, J. K.; Clyde, W. C.; Bothner, W. A.; Gardner, J. V.

    2008-12-01

    Since 2003, four cruises on the icebreaker USCG HEALY have collected high-resolution multibeam sonar mapping data in the Amerasia Basin in support of a potential submission by the U.S. for an extended continental shelf as defined under the United Nations Convention on Law of the Sea Article 76. The latest of these cruises (HEALY0805), completed in early Sept.of 2008, extended this mapping to the southern portions of the Alpha/Mendeleev Ridge complex, and supplemented the mapping with seven dredge stations, providing rare, direct sampling of both regions. While sparse in comparison to complete-coverage multibeam sonar surveys (due to the difficulties associated with operating in ice-covered waters), the new multibeam sonar data still provide an unprecedented new view of the tectonic, sedimentary, glacial and fluid- flow related processes in the Arctic Ocean. The Chukchi Borderland is characterized by shallow plateaus that often show evidence of interaction with icebergs and glaciers (scours and grooves) at depths as great as 900 m, as well as the presence of numerous gas/fluid expulsion features (pockmarks and acoustic wipe-out zones). The topographic highs associated with the Borderland are often bounded by very steep scarps including the eastern edge of Northwind Ridge (the Northwind Escarpment) which is a 600 km long NNE trending feature with an average slope of 10-15 degrees. Similar steep-sided ridges, separated by deep linear valleys also appear in mapped areas of the Alpha/Mendeleev Ridge complex. Some of these features have slopes as great at 60 degrees and thus are excellent targets for dredging. Our dredging of these slopes has returned a wide array of volcanic and sedimentary rock types, many of which appear to be representative of outcrops (rather than ice rafted material). A preliminary shipboard examination of these samples (they were just collected this morning - 3 September 2008 - a few days before the abstract is due) shows them to include mudstone

  5. Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments from the Bering Sea and western Arctic Ocean.

    Science.gov (United States)

    Zhao, Mengwei; Wang, Weiguo; Liu, Yanguang; Dong, Linsen; Jiao, Liping; Hu, Limin; Fan, Dejiang

    2016-03-15

    To analyze the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) and evaluate their potential ecological risks, the concentrations of 16 PAHs were measured in 43 surface sediment samples from the Bering Sea and western Arctic Ocean. Total PAH (tPAH) concentrations ranged from 36.95 to 150.21 ng/g (dry weight). In descending order, the surface sediment tPAH concentrations were as follows: Canada Basin>northern Chukchi Sea>Chukchi Basin>southern Chukchi Sea>Aleutian Basin>Makarov Basin>Bering Sea shelf. The Bering Sea and western Arctic Ocean mainly received PAHs of pyrogenic origin due to pollution caused by the incomplete combustion of fossil fuels. The concentrations of PAHs in the sediments of the study areas did not exceed effects range low (ERL) values.

  6. Study of Under-ice Blooms In the Chukchi Ecosystem (SUBICE) (HLY1401, EM122)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The primary objectives of SUBICE were to determine the spatial distribution of large under-ice phytoplankton blooms on the Chukchi Shelf and the physical mechanisms...

  7. Gray whale sightings in the Canadian Beaufort Sea, September 2014

    Science.gov (United States)

    Iwahara, Yuka; Fujiwara, Amane; Ito, Keizo; Miyashita, Kazushi; Mitani, Yoko

    2016-06-01

    Gray whales (Eschrichtius robustus) are distributed within the productive neritic and estuarine waters of the North Pacific Ocean, the Bering Sea, and adjacent waters of the Arctic Ocean. They migrate to high-latitude feeding grounds each spring. Their main feeding grounds in the Arctic include the Chirikov Basin, the northeastern Chukchi Sea from Pt. Hope to Cape Lisburne and Pt. Lay to Pt. Barrow, and the northwestern Chukchi Sea along the Chukotka coast. Although sightings are rare in the Canadian Beaufort Sea, we observed three gray whales in two groups in this area in September 2014. A mud plume was observed near one of the whales, suggesting the animal had been feeding. In the Alaskan Beaufort Sea, large-scale monitoring of the distributions of marine mammals has been continuously conducted since 1979; however, there has been less monitoring in the Canadian Beaufort Sea. Therefore, it is necessary to record opportunistic sightings, such as those described here.

  8. The role of atmospheric synoptic conditions in the Beaufort and Chukchi seasonal ice zone

    Science.gov (United States)

    Liu, Z.; Schweiger, A. J. B.

    2015-12-01

    How atmosphere and sea ice interact depends on the prevailing weather. Synoptic activities transport energy and moisture into the Arctic and modify the structure of the atmosphere, cloud conditions, and the surface energy budget over sea ice. The structure of the atmosphere, such as temperature inversions and specific humidity inversions are critical for the life cycle of Arctic clouds. Cloud radiative heating is an important component of the Arctic surface energy budget. The differences in the structure of the atmosphere, clouds, and the radiation balance at the surface under different synoptic conditions will determine which processes will govern the interaction between the atmosphere and clouds. In this study, dominant synoptic types over the Beaufort and Chukchi seasonal ice zone (BCSIZ) are identified using the ERA-Interim reanalysis data sets and a k-mean clustering synoptic classification algorithm. The synoptic classification algorithm categorizes individual weather events in the atmospheric reanalysis into four synoptic types with distinct signatures in baroclinicity and temperature advection. The typical structure of the atmosphere in ERA-Interim is determined for each synoptic type. In particular the structure of the summer atmosphere across the ice edge along 150°W and 140°W longitude will be the analyzed and evaluated with observations obtained from the Seasonal Ice Zone Reconnaissance Survey (SIZRS). Cloud conditions and cloud radiative forcings at the surface under different synoptic conditions are determined using satellite observations, from MODIS, CloudSat, and Calipso, and modeled clouds in reanalysis. The influence of synoptic conditions on the structure of atmosphere and cloud through heat and moisture transport is explored and the consequent effects on the surface energy budget in BCSIZ are assessed.

  9. Pacific Walrus Response to Arctic Sea Ice Losses

    Science.gov (United States)

    Jay, Chadwick V.; Fischbach, Anthony S.

    2008-01-01

    Sea ice plays an important role in the life of the Pacific walrus (Odobenus rosmarus divergens). U.S. Geological Survey (USGS) scientists are seeking to understand how losses of sea ice during summer over important foraging grounds in the Chukchi Sea will affect walruses. USGS scientists recently modified a remotely deployed satellite radio-tag that will aid in studying walrus foraging habitats and behaviors. Information from the tags will help USGS understand how walruses are responding to their changing environment.

  10. Cretaceous–Cenozoic burial and exhumation history of the Chukchi shelf, offshore Arctic Alaska

    Science.gov (United States)

    Craddock, William H.; Houseknecht, David W.

    2016-01-01

    Apatite fission track (AFT) and vitrinite reflectance data from five exploration wells and three seafloor cores illuminate the thermal history of the underexplored United States Chukchi shelf. On the northeastern shelf, Triassic strata in the Chevron 1 Diamond well record apatite annealing followed by cooling, possibly during the Triassic to Middle Jurassic, which is a thermal history likely related to Canada Basin rifting. Jurassic strata exhumed in the hanging wall of the frontal Herald Arch thrust fault record a history of probable Late Jurassic to Early Cretaceous structural burial in the Chukotka fold and thrust belt, followed by rapid exhumation to near-surface temperatures at 104 ± 30 Ma. This history of contractional tectonism is in good agreement with inherited fission track ages in low-thermal-maturity, Cretaceous–Cenozoic strata in the Chukchi foreland, providing complementary evidence for the timing of exhumation and suggesting a source-to-sink relationship. In the central Chukchi foreland, inverse modeling of reset AFT samples from the Shell 1 Klondike and Shell 1 Crackerjack wells reveals several tens of degrees of cooling from maximum paleo-temperatures, with maximum heating permissible at any time from about 100 to 50 Ma, and cooling persisting to as recent as 30 Ma. Similar histories are compatible with partially reset AFT samples from other Chukchi wells (Shell 1 Popcorn, Shell 1 Burger, and Chevron 1 Diamond) and are probable in light of regional geologic evidence. Given geologic context provided by regional seismic reflection data, we interpret these inverse models to reveal a Late Cretaceous episode of cyclical burial and erosion across the central Chukchi shelf, possibly partially overprinted by Cenozoic cooling related to decreasing surface temperatures. Regionally, we interpret this kinematic history to be reflective of moderate, transpressional deformation of the Chukchi shelf during the final phases of contractional tectonism in the

  11. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification

    Science.gov (United States)

    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju

    2016-09-01

    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents-Kara seas. Excessive turbulent heat flux through the sea surface exposed to air due to sea ice reduction warms the atmospheric column. Warmer air increases the downward longwave radiation and subsequently surface air temperature, which facilitates sea surface remains to be free of ice. This positive feedback mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. A detailed seasonal heat budget is presented in order to understand specific differences between the Barents-Kara seas and Laptev, East Siberian, Chukchi, and Beaufort seas.

  12. Massive phytoplankton blooms under Arctic sea ice.

    Science.gov (United States)

    Arrigo, Kevin R; Perovich, Donald K; Pickart, Robert S; Brown, Zachary W; van Dijken, Gert L; Lowry, Kate E; Mills, Matthew M; Palmer, Molly A; Balch, William M; Bahr, Frank; Bates, Nicholas R; Benitez-Nelson, Claudia; Bowler, Bruce; Brownlee, Emily; Ehn, Jens K; Frey, Karen E; Garley, Rebecca; Laney, Samuel R; Lubelczyk, Laura; Mathis, Jeremy; Matsuoka, Atsushi; Mitchell, B Greg; Moore, G W K; Ortega-Retuerta, Eva; Pal, Sharmila; Polashenski, Chris M; Reynolds, Rick A; Schieber, Brian; Sosik, Heidi M; Stephens, Michael; Swift, James H

    2012-06-15

    Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt ponds. The bloom was characterized by high diatom biomass and rates of growth and primary production. Evidence suggests that under-ice phytoplankton blooms may be more widespread over nutrient-rich Arctic continental shelves and that satellite-based estimates of annual primary production in these waters may be underestimated by up to 10-fold.

  13. A Holocene cryptotephra record from the Chukchi margin: the first tephrostratigraphic study in the Arctic Ocean

    OpenAIRE

    Ponomareva, Vera; Polyak, Leonid; Portnyagin, Maxim; Abbott, Peter; Davies, Siwan

    2014-01-01

    Developing geochronology for sediments in the Arctic Ocean and its continental margins is an important but challenging task complicated by multiple problems. In particular, the Chukchi/Beaufort margin, a critical area for reconstructing paleoceanographic conditions in the Pacific sector of the Arctic, features widespread dissolution of calcareous material, which limits posibilities for radiocarbon chronology. In order to evaluate the untapped potential of tephrochronology for constraining the...

  14. Characterizing Arctic sea ice topography using high-resolution IceBridge data

    OpenAIRE

    Petty, Alek A.; Tsamados, Michel C.; Kurtz, Nathan T.; Farrell, Sinead L.; Newman, Thomas; Harbeck, Jeremy P.; FELTHAM, DANIEL L.; Richter-Menge, Jackie A.

    2015-01-01

    We present an analysis of Arctic sea ice topography using high resolution, three-dimensional, surface elevation data from the Airborne Topographic Mapper, flown as part of NASA's Operation IceBridge mission. Surface features in the sea ice cover are detected using a newly developed surface feature picking algorithm. We derive information regarding the height, volume and geometry of surface features from 2009–2014 within the Beaufort/Chukchi and Central Arcti...

  15. Wave-Ice and Air-Ice-Ocean Interaction During the Chukchi Sea Ice Edge Advance

    Science.gov (United States)

    2014-09-30

    Ocean gliders Ahead of ice edge Upper ocean (0-200m) T, S, O2, bio- optics , currents During cruise CU-B UAF Autonomous underwater vehicle (AUV...Under ice, up to 50km transects Ice thickness, floe-size distribution, waves, upper ocean properties ADCP, CTD, camera, multibeam sonar...WBMS broadband multibeam sonar, a Nortek 500 kHz AD2CP, and a hyperspectral radiometer. A Seabird Fastcat-49 CTD will also be added. This ROV will

  16. 75 FR 803 - Safety Zone; FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Sea...

    Science.gov (United States)

    2010-01-06

    ... DISCOVERER, while anchored on location in order to drill exploratory wells at various prospects located in... and Request for Comments'' portion of the SUPPLEMENTARY INFORMATION section below for instructions on... around the DRILLSHIP FRONTIER DISCOVERER while anchored on location in order to drill exploratory...

  17. Observed features of temperature, salinity and current in central Chukchi Sea during the summer of 2012

    Institute of Scientific and Technical Information of China (English)

    HE Yan; LIU Na; CHEN Hongxia; TENG Fei; LIN Lina; WANG Huiwu

    2015-01-01

    During the summer of 2012, the fifth CHINARE Arctic Expedition was carried out, and a submersible mooring system was deployed in M5 station located at (69°30.155'N,169°00.654'W) and recovered 50d later. A set of temperature, salinity and current profile records was acquired. The characteristics of these observations are analyzed in this paper. Some main results are achieved as below. (1) Temperature generally decreases while salinity generally increases with increasing depth. The average values of all records are 2.98℃ and 32.21 psu. (2) Salinity and temperature are well negatively correlated, and the correlation coefficient between them is –0.84. However, they did not always vary synchronously. Their co-variation featured different characters during different significant periods. (3) The average velocity for the whole water column is 141 mm/s with directional angle of 347.1°. The statistical distribution curve of velocity record number gets narrower with increasing depth. More than 85% of the recorded velocities are northward, and the mean magnitudes of dominated northward velocities are 100–150 mm/s. (4) Rotary spectrum analysis shows that motions with low frequency take a majority of energy in all layers. The most significant energy peaks for all layers are around 0.012 cph (about 3.5 d period), while the tidal motion in mooring area is nonsignificant. (5) Velocities in all layers feature similar and synchronous temporal variations, except for the slight decrease in magnitude and leftward twist from top to bottom. The directions of velocity correspond well to those of surface wind. The average northward volume transport per square meter is 0.1–0.2 m3/s under southerly wind, but about –0.2 m3/s during northerly wind burst.

  18. AFSC/RACE/EcoFOCI: 2011 Chukchi Sea Cruise MB11-01/1MB11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A total of 64 stations were occupied along onshore-offshore transect lines from the Bering Strait to Barrow Canyon. At each station we sampled zooplankton using a...

  19. Aerial Surveys of Endangered Whales in the Beaufort, Eastern Chukchi, and Northern Bearing Seas, 1982.

    Science.gov (United States)

    1983-06-01

    3000 ft). Th~ese images of the meter stick were measured and used in an attempt to calibrate the measurement of wales from photographs. 101 I I S1. Time...APRIL, MAY) survey Effort and Rationale I In the spring, flight effort was designed to find and follow bowhead wales migrating northward through the... beluga whale in Alaska. Alaska Department of Fish and Game. Federal Arctic Wildlife Restoration Project Report, Vol. 7. Krogman, BD, RM Sonntag, DJ Rugh, J

  20. Aerial Surveys of Endangered Whales in the Beaufort, Chukchi & Northern Bering Seas.

    Science.gov (United States)

    1982-03-01

    sighted north of Cape Prince of Wales . One hundred and sixty-seven beluga , including cow-calf pairs, and 15 aringed seals including cow-pup pairs were... Wales and Cape Sabine), 4 belugas at Pt. Lay, and 3 walrus. 168 165 162 159 156 153 150 71 71 70 - 70 69 69 68 68 67 67 67 ___ 1 .KEY FOR FLIGHT 89 66...sonobuoys, that beluga whales were present. Currently we assume that problems *of sightability are smoothed over time through repetitive sampling of an

  1. Recent changes in Arctic sea ice melt onset, freezeup, and melt season length

    Science.gov (United States)

    Markus, Thorsten; Stroeve, Julienne C.; Miller, Jeffrey

    2009-12-01

    In order to explore changes and trends in the timing of Arctic sea ice melt onset and freezeup, and therefore melt season length, we developed a method that obtains this information directly from satellite passive microwave data, creating a consistent data set from 1979 through present. We furthermore distinguish between early melt (the first day of the year when melt is detected) and the first day of continuous melt. A similar distinction is made for the freezeup. Using this method we analyze trends in melt onset and freezeup for 10 different Arctic regions. In all regions except for the Sea of Okhotsk, which shows a very slight and statistically insignificant positive trend (0.4 d decade-1), trends in melt onset are negative, i.e., toward earlier melt. The trends range from -1.0 d decade-1 for the Bering Sea to -7.3 d decade-1 for the East Greenland Sea. Except for the Sea of Okhotsk all areas also show a trend toward later autumn freeze onset. The Chukchi/Beaufort seas and Laptev/East Siberian seas observe the strongest trends with 7 d decade-1. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 10 d decade-1 are seen for Hudson Bay, the East Greenland Sea, the Laptev/East Siberian seas, and the Chukchi/Beaufort seas. Those trends are statistically significant at the 99% level.

  2. Ice rafting history and paleoceanographic reconstructions of Core 08P23 from southern Chukchi Plateau, western Arctic Ocean since Marine Isotope Stage 3

    Institute of Scientific and Technical Information of China (English)

    ZHANG Taoliang; WANG Rujian; XIAO Wenshen; CHEN Zhihua; CHEN Jianfang; CHENG Zhenbo; SUN Yechen

    2015-01-01

    Multiproxy investigations have been performed on Core 08P23 collected from the Chukchi Plateau, the western Arctic Ocean, during the Third Chinese National Arctic Expedition. The core was dated back to Ma-rine Isotope Stage (MIS) 3 by a combination of Accelerator Mass Spectrometric (AMS) carbon-14 dating and regional core correlation. A total of five prominent ice-rafted detritus (IRD) events were recognized in MIS 2 and MIS 3. The IRD sources in MIS 3 are originated from vast carbonate rock outcrops of the Canadian Arctic Archipelago and clastic quartz in MIS 2 may have a Eurasian origin. Mostδ18O andδ13C values of Neogloboquadrina pachyderma (sinistral) (Nps) in Core 08P23 are lighter than the average values of surface sediments. The lighterδ18O andδ13C values of Nps in the two brown layers in MIS 1 and MIS 3 were resulted from meltwater events; and those in the gray layers in MIS 3 were caused by the enhanced sea ice formation. Theδ18O values varied inversely withδ13C in MIS 2 indicate that the study area was covered by thick sea ice or ice sheet with low temperature and little meltwater, which prevented the biological productivity and sea-atmosphere exchange, as well as water mass ventilation. The covaried light values ofδ18O andδ13C in MIS 1 and MIS 3 were resulted from meltwater and/or brine injection.

  3. Walrus Bayesian State-space Model Output from the Bering Sea and Chukchi Sea, 2008-2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — State-space models offer researchers an objective approach to modeling complex animal location datasets, and state-space model behavior classifications are often...

  4. A baseline study of historic ice conditions in the Beaufort Sea, Chukchi Sea, and Bering Strait: Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Final report under Outer Continental Shelf contract 03-5-022-55 or 2611262, also published with revised pagination in Environmental Assessment of the Alaskan...

  5. Sea ice dynamics and the role of wind forcing over the Beaufort Sea

    Science.gov (United States)

    Petty, A.; Hutchings, J. K.; Farrell, S. L.; Richter-Menge, J.; Tschudi, M. A.

    2014-12-01

    Both the ocean circulation and overlying sea ice cover of the Beaufort and Chukchi seas have experienced significant change in recent decades. We use sea ice drift estimates from satellite feature tracking (NSIDC/CERSAT), wind forcing from atmospheric reanalysis products (NCEP-R2/ERA-I/JRA-55), and ice type information from satellite and direct ship-based observations (obtained during the Beaufort Gyre Exploration Project), to investigate the role of wind forcing and ice mechanics in driving these changes. An assessment of ice drift shows reasonable agreement across the different products, revealing interannual variability in the ice flux around the Beaufort Sea. However, clear uncertainties remain in determining the magnitude of these fluxes, especially in regions of low ice concentration. We find an increase in ice export out of the southern Beaufort Sea (into the Chukchi Sea) across all seasons. We find slight differences in the strength of the decadal (1980-2013) trends in the mean seasonal wind curl over the Beaufort Sea, although all reanalysis products indicate a strong and significant increase in anti-cyclonic winds in summer. Analysis of ice drift curl suggests increasing anti-cyclonic drift across all seasons, despite the wind curl showing a similar trend in summer only. The strongest trend in ice drift curl appears to be in autumn, however recent years have seen a strong reduction in this anti-cyclonic drift, likely due to a combination of changes in the wind forcing and sea ice state. The implication of this finding is an enhanced response of the ocean circulation to shifts in atmospheric circulation compared to that experienced prior to 2000.

  6. U-Pb zircon geochronology of Caledonian age orthogneisses dredged from the Chukchi Borderland, Arctic Ocean.

    Science.gov (United States)

    Brumley, K.; Miller, E. L.; Mayer, L. A.; Wooden, J.; Grove, M.

    2012-04-01

    Over 500 kilos of metamorphic rock was dredged from outcrops along a steep normal fault scarp in the central Chukchi Borderland in 2009 (HLY0905) from water depths of between about 2500-1400m. The rocks in the dredge included broken angular cobbles and boulder-sized samples of amphibolites, orthogneisses, and granitoids of the same amphibolite facies metamorphic grade, as well as gravel to small cobble-sized ice rafted debris of various rock types. Zircons were separated from two of the orthogneiss samples, and single grain zircon U-Pb ages were determined by SHRIMP analysis to be 428 Ma ± 3.4 for both samples (N=60). Several zircon grains had distinct igneous cores that ranged in age from about 928-1200 Ma (n=7) with two older grains (1700, 1760 Ma). The Caledonian orogenic belt developed in the Ordovician to Devonian affecting northern Europe, Greenland and Arctic Canada. Caledonian deformational trends continue into the Arctic and disappear at the rifted margin of the Arctic Ocean. Syn-orogenic magmatism in the Barents region date deformation in this region during the Caledonian event to have occurred between about 450-410 Ma (Johansson et al., 2005; Gee et al., 2006; Gee and Tebenkov, 2004). Grenville age plutons (900-1250Ma) that were later involved in Caledonian deformation and intruded by 410-450 Ma aged plutons are found on western and eastern Svalbard (Johansson et al., 2005), eastern Greenland, and the Pearya Terrane of northern Ellesmere Island (Trettin,1986, 1992). The Franklinian basement of Arctic Alaska and Canada do not share these Grenvillian ages (Trentin et al, 1987). This suggests that the inherited zircon cores in the Chukchi Borderland orthogneisses were derived, at least in part, from an older Grenvillian basement like that of Pearya, Svalbard and parts of Greenland, or through sediments eroded from these sources, and later intruded by Caledonian aged granites. This constrains the pre-rift location of the Chukchi Borderland to be within the

  7. Interdecadal changes in snow depth on Arctic sea ice

    Science.gov (United States)

    Webster, Melinda A.; Rigor, Ignatius G.; Nghiem, Son V.; Kurtz, Nathan T.; Farrell, Sinead L.; Perovich, Donald K.; Sturm, Matthew

    2014-08-01

    Snow plays a key role in the growth and decay of Arctic sea ice. In winter, it insulates sea ice from cold air temperatures, slowing sea ice growth. From spring to summer, the albedo of snow determines how much insolation is absorbed by the sea ice and underlying ocean, impacting ice melt processes. Knowledge of the contemporary snow depth distribution is essential for estimating sea ice thickness and volume, and for understanding and modeling sea ice thermodynamics in the changing Arctic. This study assesses spring snow depth distribution on Arctic sea ice using airborne radar observations from Operation IceBridge for 2009-2013. Data were validated using coordinated in situ measurements taken in March 2012 during the Bromine, Ozone, and Mercury Experiment (BROMEX) field campaign. We find a correlation of 0.59 and root-mean-square error of 5.8 cm between the airborne and in situ data. Using this relationship and IceBridge snow thickness products, we compared the recent results with data from the 1937, 1954-1991 Soviet drifting ice stations. The comparison shows thinning of the snowpack, from 35.1 ± 9.4 to 22.2 ± 1.9 cm in the western Arctic, and from 32.8 ± 9.4 to 14.5 ± 1.9 cm in the Beaufort and Chukchi seas. These changes suggest a snow depth decline of 37 ± 29% in the western Arctic and 56 ± 33% in the Beaufort and Chukchi seas. Thinning is negatively correlated with the delayed onset of sea ice freezeup during autumn.

  8. Diagnostic sea ice predictability in the pan-Arctic and U.S. Arctic regional seas

    Science.gov (United States)

    Cheng, Wei; Blanchard-Wrigglesworth, Edward; Bitz, Cecilia M.; Ladd, Carol; Stabeno, Phyllis J.

    2016-11-01

    This study assesses sea ice predictability in the pan-Arctic and U.S. Arctic regional (Bering, Chukchi, and Beaufort) seas with a purpose of understanding regional differences from the pan-Arctic perspective and how predictability might change under changing climate. Lagged correlation is derived using existing output from the Community Earth System Model Large Ensemble (CESM-LE), Pan-Arctic Ice-Ocean Modeling and Assimilation System, and NOAA Coupled Forecast System Reanalysis models. While qualitatively similar, quantitative differences exist in Arctic ice area lagged correlation in models with or without data assimilation. On regional scales, modeled ice area lagged correlations are strongly location and season dependent. A robust feature in the CESM-LE is that the pan-Arctic melt-to-freeze season ice area memory intensifies, whereas the freeze-to-melt season memory weakens as climate warms, but there are across-region variations in the sea ice predictability changes with changing climate.

  9. Snow melt on sea ice surfaces as determined from passive microwave satellite data

    Science.gov (United States)

    Anderson, Mark R.

    1987-01-01

    SMMR data for the year 1979, 1980 and 1984 have been analyzed to determine the variability in the onset of melt for the Arctic seasonal sea ice zone. The results show melt commencing in either the Kara/Barents Seas or Chukchi Sea and progressing zonally towards the central Asian coast (Laptev Sea). Individual regions had interannual variations in melt onset in the 10-20 day range. To determine whether daily changes occur in the sea ice surface melt, the SMMR 18 and 37 GHz brightness temperature data are analyzed at day/night/twilight periods. Brightness temperatures illustrate diurnal variations in most regions during melt. In the East Siberian Sea, however, daily variations are observed in 1979, throughout the analysis period, well before any melt would usually have commenced. Understanding microwave responses to changing surface conditions during melt will perhaps give additional information about energy budgets during the winter to summer transition of sea ice.

  10. Singular Value Decomposition Analysis of Cloud Fraction Cover and Sea Ice Concentration over the Arctic Region, 1982-2009

    Science.gov (United States)

    Boccolari, Mauro; Parmiggiani, Flavio

    2016-08-01

    In this study, the coupled spatial and temporal variability between seasonal data of Cloud Fraction Cover (CFC) and Sea Ice Concentration (SIC) in the Arctic Ocean for the 1982-2009 period were investigated by using the Singular Value Decomposition (SVD) method.The spatial patterns of CFCs related to the first mode of co-variability, identify the maximum covariance, for all seasons, in the Barents Sea and in the Arctic Ocean Canada, while the SIC and 'found in the Chukchi Sea in autumn (in according to the maximum sea ice melting) and the Barents sea during both the winter and spring.CFC spatial patterns related to the first mode of co- variability, locate maximum covariance, for all seasons, in the Barents Sea and in the Canadian side of the Arctic Ocean, while for SIC is found in the Chukchi Sea during autumn (corresponding to the maximum sea ice melting) and in the Barents Sea during both the winter and spring.Finally, the correlation between the seasonal time series of expansion coefficients derived from the SVD analysis, for both CFC and SIC fields, with the seasonal time series of some relevant climate indices for the Arctic (NAO, AO, PDO and PNA). Statistically significant values for both fields were found during summer with the AO, and during autumn with the PNA.

  11. First Recovery of Submarine Basalts from the Chukchi Borderland and Alpha / Mendeleev Ridge, Arctic Ocean

    Science.gov (United States)

    Andronikov, A.; Mukasa, S.; Mayer, L. A.; Brumley, K.

    2008-12-01

    In addition to multibeam bathymetric mapping of the Amerasia Basin in the high Arctic Ocean, the August- September 2008 cruise of USCGC Icebreaker HEALY (HLY0805) conducted a total of seven dredging profiles along the southern sectors of the Alpha/Mendeleev Ridge and in the northernmost region of Northwind Ridge of Chukchi Borderland. Five of the seven dredges were recovered on relatively gentle slopes (30-40°) and yielded mostly mud with a small number of fragments of sedimentary rocks and ice rafted debris (IRD), which indicates either rapid sedimentation rates on the bathymetrically high features sampled or lack of recently active volcanism on these features. Two dredges taken from steep escarpments with slopes (> 55°) at >3.5 km depth recovered some of the first known submarine basaltic samples from the Arctic Ocean floor away from the Gakkel Ridge. Ragged, freshly exposed edges indicate that these samples were broken from outcrop rather than being IRD. In some cases (e.g., a rise on the ocean floor between the Alpha/Mendeleev Ridge and Northwind Ridge) the samples have well-preserved pillow-basalt structures with fresh glassy rims up to 4 cm thick. Inward from the rims, the rocks are dark-grey lavas, some with visible plagioclase laths and rare phenocrysts up to 0.5 mm in length, some with visible signs of alteration such as local occurrence of chlorite. Surfaces that were exposed to water can be covered with a thin black film of Mn oxides. Occurrence of this volcanism away from any obvious spreading centers compels us to hypothesize that forthcoming geochemical analyses are likely to identify these rocks as the first Arctic Ocean floor samples to exhibit ocean island basalt compositions. The dredge taken from the northern slope of Northwind Ridge, along slopes as steep as > 45°, recovered a variety of rock types including sedimentary and basaltic rocks. Some of the basalts have columnar jointing (the size of the columns is only up to 5-6 cm across

  12. Arctic and Antarctic sea ice and climate

    Science.gov (United States)

    Barreira, S.

    2014-12-01

    Principal Components Analysis in T-Mode Varimax rotated was performed on Antarctic and Arctic monthly sea ice concentration anomalies (SICA) fields for the period 1979-2014, in order to investigate which are the main spatial characteristics of sea ice and its relationship with atmospheric circulation. This analysis provides 5 patterns of sea ice for inter-spring period and 3 patterns for summer-autumn for Antarctica (69,2% of the total variance) and 3 different patterns for summer-autumn and 3 for winter-spring season for the Arctic Ocean (67,8% of the total variance).Each of these patterns has a positive and negative phase. We used the Monthly Polar Gridded Sea Ice Concentrations database derived from satellite information generated by NASA Team algorithm. To understand the links between the SICA and climate trends, we extracted the mean pressure and, temperature field patterns for the months with high loadings (positive or negative) of the sea ice patterns that gave distinct atmospheric structures associated with each one. For Antarctica, the first SICA spatial winter-spring pattern in positive phase shows a negative SICA centre over the Drake Passage and north region of Bellingshausen and Weddell Seas together with another negative SICA centre over the East Indian Ocean. Strong positive centres over the rest of the Atlantic and Indian Oceans basins and the Amundsen Sea are also presented. A strong negative pressure anomaly covers most of the Antarctic Continent centered over the Bellingshausen Sea accompanied by three positive pressure anomalies in middle-latitudes. During recent years, the Arctic showed persistent associations of sea-ice and climate patterns principally during summer. Our strongest summer-autumn pattern in negative phase showed a marked reduction on SICA over western Arctic, primarily linked to an overall increase in Arctic atmospheric temperature most pronounced over the Beaufort, Chukchi and East Siberian Seas, and a positive anomaly of

  13. The Caledonian suture in the high Arctic? New data from the Chukchi Borderland, Amerasia Basin

    Science.gov (United States)

    O'Brien, T.; Brumley, K. J.; Miller, E. L.; Mayer, L. A.

    2013-12-01

    The Chukchi Borderland (CB) is a bathymetric high in the Arctic Ocean that is extended by N-S and E-W striking faults. Based on sediment cores of talus slope fragments at the base of the Northwind Ridge (NWR), basement of the CB was previously interpreted as a Paleozoic platform sequence comparable to passive margin strata of western Laurentia (Grantz et al., 1998). The discovery of Silurian (~430 Ma) orthogneiss dredged from a fault scarp in the central CB suggests instead that the CB is a displaced fragment of the Caledonian orogen (Brumley et al., 2008). U-Pb geochronology of zircon suites from rocks dredged from the NWR and central CB fault scarps help resolve the make-up of the CB basement. Samples from the central CB are believed to represent the country rocks of the previously dated Silurian orthogneiss. They consist mostly of paragneiss and lesser orthogneiss intruded by leucosomal segregations, all deformed and metamorphosed to amphibolite facies with assemblages Qtz + Kfs + Plag + Bt + Grt × Ms × Chl (retrograde) with accessory zircon, sphene and apatite. The abundance of Kfs + Plag + Bt in paragneiss samples suggest a volcanogenic sediment protolith. Dynamic recrystallization of quartz by grain-boundary migration and recrystallization/myrmekite development along the edges of feldspar crystals suggest final deformation at temperatures of ~450 C. U-Pb geochronology of zircon from an orthogneiss sample from the central CB yields an age of 499.2 × 0.9 Ma with late Neoproterozoic (600 Ma) and Mesoproterozoic - early Paleoproterozoic (1100-1700 Ma) grains. Detrital zircon geochronology from four paragneiss samples show a broad range of ages between 480-650 Ma with a dominant age peak ~500 Ma. Lesser, mostly discordant, Mesoproterozoic and Paleoproterozoic zircons are also present. The paragneiss sampled represent an arc-proximal sediment intruded by Silurian granitoids. Dredge samples from the NWR consist of deformed and metamorphosed calcareous sandstones

  14. Dietary exposure to persistent organic pollutants and metals among Inuit and Chukchi in Russian Arctic Chukotka

    Directory of Open Access Journals (Sweden)

    Alexey A. Dudarev

    2012-07-01

    Full Text Available Objectives. The general aim was to assess dietary exposure to selected persistent organic pollutants (POPs and metals among Eskimo (Inuit and Chukchi of the Chukotka Peninsula of the Russian Arctic, and to establish recommendations for exposure risk reduction. Study design. A cross-sectional evaluation of nutritional patterns of coastal and inland indigenous peoples of the Chukotka Autonomous Okrug (in 2001–2003; assessment of the levels of persistent toxic substances (PTSs in traditional foods and their comparison to Russian food safety limits; the identification of local sources of food contamination; and the recommendation and implementation of risk management measures. Methods. Community-based dietary survey of self reported food frequencies (453 persons, chemical analyses (POPs and metals of local foods and indoor matters (397 samples, substantiation of recommendations for daily (weekly, monthly intakes of traditional food. Results. POPs in traditional food items are generally below the Russian food safety limits except marine mammal fat, while Hg and Cd are high mainly in mammal viscera. Lead is relatively low in tissues of all animals studied. For the Chukotka coastal communities, seals constitute the principal source of the whole suite of PTSs considered. Consumption restrictions are recommended for marine and freshwater fish, some wild meats (waterfowl and seal, fats (whale and seal, liver (most animals and kidney (reindeer, walrus and seal. Evidence is presented that contamination of foodstuffs may be significantly increased during storing/processing/cooking of food due to indoor and outdoor environmental conditions. Conclusions. Based on the analytical findings and the local PTSs sources identified, guidelines on food safety are suggested, as well as measures to reduce food contamination and domestic and local sources. Important and urgent remedial actions are recommended to minimize PTSs environmental and domestic contamination

  15. Recent Changes in Arctic Sea Ice Melt Onset, Freeze-Up, and Melt Season Length

    Science.gov (United States)

    Markus, Thorsten; Stroeve, Julienne C.; Miller, Jeffrey

    2010-01-01

    In order to explore changes and trends in the timing of Arctic sea ice melt onset and freeze-up and therefore melt season length, we developed a method that obtains this information directly from satellite passive microwave data, creating a consistent data set from 1979 through present. We furthermore distinguish between early melt (the first day of the year when melt is detected) and the first day of continuous melt. A similar distinction is made for the freeze-up. Using this method we analyze trends in melt onset and freeze-up for 10 different Arctic regions. In all regions except for the Sea of Okhotsk, which shows a very slight and statistically insignificant positive trend (O.4 days/decade), trends in melt onset are negative, i.e. towards earlier melt. The trends range from -1.0day/decade for the Bering Sea to -7.3 days/decade for the East Greenland Sea. Except for the Sea of Okhotsk all areas also show a trend towards later autumn freeze onset. The Chukchi/Beaufort Seas and Laptev/East Siberian Seas observe the strongest trends with 7 days/decade. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 1O days/decade are seen for Hudson Bay, the East Greenland Sea the Laptev/East Siberian Seas, and the Chukchi/Beaufort Seas. Those trends are statistically significant a1 the 99% level.

  16. Lithostratigraphy and paleoceanography in the Chukchi Rise of the western Arctic Ocean since the last glacial period

    Science.gov (United States)

    Park, Kwangkyu; Ohkushi, Ken'ichi; Cho, Hyen Goo; Khim, Boo-Keun

    2017-03-01

    Paleoceanographic multi-proxies were investigated from two piston cores PC01 and PC04, along with two pilot cores PL01 and PL04, collected from the Chukchi Rise in the western Arctic Ocean during the R/V Mirai Cruise MR09-03. Both cores were composed of three lithologic units (Unit I: the Holocene brownish sandy mud, Unit II: the deglacial IRD layer, and Unit III: the glacial and gray thick mud with intervened IRD layers). The age estimate of the core units were decided by AMS 14C dates and confirmed by the correlation of the geochemical properties and ice-rafted debris (IRD) pattern with the well-dated core (P2) in the study area. The geochemical, isotopic, and mineralogical properties indicate different paleoceanographic conditions of three lithologic units in the Chukchi Rise: low primary production during the glacial period (Unit III), high terrigenous contribution during the deglacial period (Unit II), and increase in diatom productivity during the late Holocene (Unit I). In particular, most IRDs were specified as detrital carbonates (calcites and dolomites) by SEM-EDS examination. The sediment source from the northern North America and the transport pathway by the Beaufort Gyre were confirmed by the isotopic signature of bulk IRDs and high kaolinite content of fine-grained particles.

  17. Phylogenetic diversity and biological activity of actinobacteria isolated from the Chukchi Shelf marine sediments in the Arctic Ocean.

    Science.gov (United States)

    Yuan, Meng; Yu, Yong; Li, Hui-Rong; Dong, Ning; Zhang, Xiao-Hua

    2014-03-06

    Marine environments are a rich source of Actinobacteria and have the potential to produce a wide variety of biologically active secondary metabolites. In this study, we used four selective isolation media to culture Actinobacteria from the sediments collected from the Chukchi Shelf in the Arctic Ocean. A total of 73 actinobacterial strains were isolated. Based on repetitive DNA fingerprinting analysis, we selected 30 representatives for partial characterization according to their phylogenetic diversity, antimicrobial activities and secondary-metabolite biosynthesis genes. Results from the 16S rRNA gene sequence analysis indicated that the 30 strains could be sorted into 18 phylotypes belonging to 14 different genera: Agrococcus, Arsenicicoccus, Arthrobacter, Brevibacterium, Citricoccus, Janibacter, Kocuria, Microbacterium, Microlunatus, Nocardioides, Nocardiopsis, Saccharopolyspora, Salinibacterium and Streptomyces. To our knowledge, this paper is the first report on the isolation of Microlunatus genus members from marine habitats. Of the 30 isolates, 11 strains exhibited antibacterial and/or antifungal activity, seven of which have activities against Bacillus subtilis and Candida albicans. All 30 strains have at least two biosynthetic genes, one-third of which possess more than four biosynthetic genes. This study demonstrates the significant diversity of Actinobacteria in the Chukchi Shelf sediment and their potential for producing biologically active compounds and novel material for genetic manipulation or combinatorial biosynthesis.

  18. 77 FR 38718 - Safety Zone; NOBLE DISCOVERER, Outer Continental Shelf Drillship, Chukchi and/or Beaufort Seas, AK

    Science.gov (United States)

    2012-06-29

    ... established shipping fairways, fueling and supply storage/ operations, and size of the crew increase the... recommended an extension of the outer boundaries of the safety zone to include the anchor chain extending from... marine casualty will present unique challenges due to the remote locations, lack of infrastructure...

  19. AFSC/NMML: Marine Mammal Aerial Surveys in the Bering, Chukchi and Beaufort Seas . 1979-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bureau of Ocean Energy Management (BOEM), formerly the Minerals Management Service (MMS), and its precursor, the Bureau of Land Management, have funded aerial...

  20. SPECIES IDENTIFICATION and Other Data from POLAR STAR From Chukchi Sea and Others from 19800504 to 19800626 (NODC Accession 9000058)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The accession contains two analogue magnetic tapes of marine mammal sounds (Whales) collected as part of Outer Continental Shelf Environmental Assessment Project...

  1. Bottom Sediment Granulometric Data for the Continental Margins of the Bering, Chukchi, East Siberia, Laptev, and Beaufort Seas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of Roberts, Richard W., University of Washington, Department of Oceanography Special Report No. 70, Bottom Sediment Granulometric Data for the...

  2. 78 FR 60892 - Outer Continental Shelf (OCS), Alaska OCS Region, Chukchi Sea Planning Area, Proposed Oil and Gas...

    Science.gov (United States)

    2013-10-02

    ..., Alaska 99503-5823. Requests for proposed exclusion areas or general proposed inclusion areas (absent a... inclusion or exclusion of acreage, temporal deferrals, and/or mitigation from the Five Year Program stage... inclusion in the sale must provide a detailed explanation of the basis for classifying each nominated...

  3. Occurrence and genotypic analysis of Trichinella species in Alaska marine-associated mammals of the Bering and Chukchi seas.

    Science.gov (United States)

    Seymour, J; Horstmann-Dehn, L; Rosa, C; Lopez, J A

    2014-02-24

    The zoonotic parasite Trichinella is the causative agent of trichinellosis outbreaks in the circumpolar Arctic. Subsistence communities are particularly prone to trichinellosis due to traditional meat preparation methods and regional presence of a freeze-tolerant Trichinella species (Trichinella nativa). This study is the first application of a validated artificial digestion method in determining incidence of Trichinella sp. in Alaskan mammals. Infection incidence in pinniped species (Erignathus barbatus, Eumetopias jubatus, Odobenus rosmarus divergens, and Pusa hispida) was low, with only 1/57 ringed seals infected. Polymerase Chain Reaction assays indicate T. nativa as the only species present in northern Alaska. Analysis of an archived polar bear (Ursus maritimus) muscle sample shows freeze-tolerance and longevity for T. nativa to -20°C for 10 years and short-term freeze resistance to -80°C when morphology was used to determine presence of live larvae. However, larval motility suggests 0% survival. An approach that combines artificial digestion with PCR based species identification has excellent potential for Trichinella sp. detection and identification of archived tissues. Overall, Trichinella in Alaskan mammals, particularly marine mammals of subsistence importance, appears to be a minor problem. These modern diagnostic techniques provide accurate insight into the presence of Trichinella in the Alaskan marine environment.

  4. Climatic Atlas of the Outer Continental Shelf Waters and Coastal Regions of Alaska. Volume 3. Chukchi-Beaufort Sea

    Science.gov (United States)

    1988-01-01

    cover P I N New Ice 2 6/10-7/10 ice cover 0 Old Ice 2+ 8/10 ice cover M Multi-year ice 9110-10/10 ice cover W Grey-white ice Source: Stirling and...is less than V, nautical mile) 04-09 HAZE. DUST, SAND, OR SMOKE "include hail, ice pellets, or snow pellets Sky Sky 09 Duststorm or sandstorm within...OF SKY DURliN PAST HOUR 70-79 SOLID PRECIPITATION NOT FALLING AS SHOWERS 30-39 (Not likely to be used in ship reports) Code figs. 79 Ic- pellets Slight

  5. Bowhead (Balaena mysticetus) and beluga (Delphinapterus leucas) whales in the Bering, Chukchi and Beaufort Seas: Annual report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reproductive activity in the bowhead whale was observed in early May near Pt. Barrow Alaska, indicating that this species may calf and breed during the northward...

  6. 76 FR 53481 - Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193

    Science.gov (United States)

    2011-08-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf, Alaska OCS Region...) announces the availability of a Final Supplemental Environmental Impact Statement (SEIS) for...

  7. 78 FR 59715 - Outer Continental Shelf (OCS), Alaska OCS Region, Chukchi Sea Planning Area, Proposed Oil and Gas...

    Science.gov (United States)

    2013-09-27

    ... Web site at http://www.boem.gov/Oil-and-Gas-Energy-Program/Mapping-and-Data/Alaska.aspx . 4... Area, Proposed Oil and Gas Lease Sale 237 AGENCY: Bureau of Ocean Energy Management (BOEM), Interior..., scheduled to be held in 2016, as included in the Proposed Final OCS Oil and Gas Leasing Program...

  8. AFSC/NMML: Bowhead Whale Feeding Ecology Study (BOWFEST): Aerial Survey in Chukchi and Beaufort Seas, 2007-2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bowhead Whale Feeding Ecology Study (BOWFEST) was initiated in May 2007 through an Interagency Agreement between the Bureau of Ocean Energy Management (BOEM)...

  9. Navy Tactical Applications Guide, Volume 8 Part 2: Arctic - East Siberian/Chukchi/Beaufort Seas. Weather Analysis and Forecast Applications

    Science.gov (United States)

    1992-12-01

    Including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson ...evident (see NTAG Vol. 6, Section IC: Fett et al., 1986). Such cloud formations are always associated with severe thunderstorms and, frequently, tomadic

  10. Distribution of detrital minerals and sediment color in western Arctic Ocean and northern Bering Sea sediments: Changes in the provenance of western Arctic Ocean sediments since the last glacial period

    Science.gov (United States)

    Kobayashi, Daisuke; Yamamoto, Masanobu; Irino, Tomohisa; Nam, Seung-Il; Park, Yu-Hyeon; Harada, Naomi; Nagashima, Kana; Chikita, Kazuhisa; Saitoh, Sei-Ichi

    2016-12-01

    This paper describes the distribution of detrital minerals and sediment color in the surface sediments of the western Arctic Ocean and the northern Bering Sea and investigates the relationship between mineral composition and sediment provenance. This relationship was used to determine the provenance of western Arctic Ocean sediments deposited during the last glacial period. Sediment color is governed by water depth, diagenesis, and mineral composition. An a*-b* diagram was used to trace color change during diagenesis in the Arctic Ocean sediments. The mineral composition of surface sediments is governed by grain size and provenance. The feldspar/quartz ratio of the sediments studied was higher on the Siberian side than on the North American side of the western Arctic Ocean. The (chlorite + kaolinite)/illite and chlorite/illite ratios were high in the Bering Sea but decrease northwards in the Chukchi Sea. Thus, these ratios are useful for provenance studies in the Chukchi Sea area as indices of the Beaufort Gyre circulation and the Bering Strait inflow. The sediments deposited during the last glacial period have a lower feldspar/quartz ratio and a higher dolomite intensity than Holocene sediments on the Chukchi Plateau, suggesting a greater contribution of North American grains during the last glacial period.

  11. Petrography and U-Pb detrital zircon geochronology of metasedimentary strata dredged from the Chukchi Borderland, Amerasia Basin, Arctic Ocean

    Science.gov (United States)

    Brumley, K.; Miller, E. L.; Mayer, L. A.; Andronikov, A.; Wooden, J. L.; Dumitru, T. A.; Elliott, B.; Gehrels, G. E.; Mukasa, S. B.

    2010-12-01

    In 2008-2009, twelve dredges were taken aboard the USCGC Healy from outcrops along the Alpha Ridge, Northern Chukchi Borderland, Northwind Ridge and the Chukchi Plateau in the Arctic Ocean as part of the U.S. Extended Continental Shelf Project. To ensure sampling of outcrop, steep bathymetric slopes (>40°) with little mud cover were identified with multibeam sonar and targeted for dredging. The first dredge from Alpha Ridge yielded volcaniclastic sedimentary rocks deposited from a phreatomagmatic eruption in shallow water (<200m). This is inconsistent with tectonic reconstructions suggesting that the Alpha Ridge was created as an oceanic plateau on deep oceanic crust of the Canada Basin. Another dredge, taken from the northern tip of Northwind Ridge, yielded metasedimentary rocks deformed under greenschist facies conditions (chlorite+white mica). These rocks are intruded and/or overlain by mid-Cretaceous alkalic basalts, also taken in this dredge, and dated by 40Ar/39Ar (plagioclase separate) to be 112±1 Ma. The metasedimentary rocks, from this single dredge, range in grain size from mud to coarse sandstone and grit which all contain grains and sub-angular clasts of volcanic, plutonic, metamorphic and fine grained sedimentary rocks as well as monocrystalline quartz, potassium feldspar, and plagioclase. All of these samples display the same bedding to foliation angle and lithology, which further indicates that they were dredged from in situ outcrop and are not random samples of ice rafted debris. Based on grain size variations and graded beds, they are interpreted as Silurian gravity flow deposits fed by proximal syn-orogenic and/or magmatic arc sources. Detrital zircons were separated from four sandstone samples of the Northwind Ridge dredge, and their U-Pb single grain ages determined by LA-MC-ICPMS and SHRIMP, (N= 393). Their detrital zircon populations are dominated by euhedral first-cycle zircon ca. 430 and 980 Ma with lesser older recycled zircons between

  12. Changes in Arctic melt season and implications for sea ice loss

    Science.gov (United States)

    Stroeve, J. C.; Markus, T.; Boisvert, L.; Miller, J.; Barrett, A.

    2014-02-01

    The Arctic-wide melt season has lengthened at a rate of 5 days decade-1 from 1979 to 2013, dominated by later autumn freezeup within the Kara, Laptev, East Siberian, Chukchi, and Beaufort seas between 6 and 11 days decade-1. While melt onset trends are generally smaller, the timing of melt onset has a large influence on the total amount of solar energy absorbed during summer. The additional heat stored in the upper ocean of approximately 752 MJ m-2 during the last decade increases sea surface temperatures by 0.5 to 1.5 °C and largely explains the observed delays in autumn freezeup within the Arctic Ocean's adjacent seas. Cumulative anomalies in total absorbed solar radiation from May through September for the most recent pentad locally exceed 300-400 MJ m-2 in the Beaufort, Chukchi, and East Siberian seas. This extra solar energy is equivalent to melting 0.97 to 1.3 m of ice during the summer.

  13. Changes in Arctic Melt Season and Implications for Sea Ice Loss

    Science.gov (United States)

    Stroeve, J. C.; Markus, T.; Boisvert, L.; Miller, J.; Barrett, A.

    2014-01-01

    The Arctic-wide melt season has lengthened at a rate of 5 days dec-1 from 1979 to 2013, dominated by later autumn freeze-up within the Kara, Laptev, East Siberian, Chukchi and Beaufort seas between 6 and 11 days dec(exp -1). While melt onset trends are generally smaller, the timing of melt onset has a large influence on the total amount of solar energy absorbed during summer. The additional heat stored in the upper ocean of approximately 752MJ m(exp -2) during the last decade, increases sea surface temperatures by 0.5 to 1.5 C and largely explains the observed delays in autumn freeze-up within the Arctic Ocean's adjacent seas. Cumulative anomalies in total absorbed solar radiation from May through September for the most recent pentad locally exceed 300-400 MJ m(exp -2) in the Beaufort, Chukchi and East Siberian seas. This extra solar energy is equivalent to melting 0.97 to 1.3 m of ice during the summer.

  14. Spring Snow Depth on Arctic Sea Ice using the IceBridge Snow Depth Product (Invited)

    Science.gov (United States)

    Webster, M.; Rigor, I. G.; Nghiem, S. V.; Kurtz, N. T.; Farrell, S. L.

    2013-12-01

    Snow has dual roles in the growth and decay of Arctic sea ice. In winter, it insulates sea ice from colder air temperatures, slowing its growth. From spring into summer, the albedo of snow determines how much insolation is transmitted through the sea ice and into the underlying ocean, ultimately impacting the progression of the summer ice melt. Knowing the snow thickness and distribution are essential for understanding and modeling sea ice thermodynamics and the surface heat budget. Therefore, an accurate assessment of the snow cover is necessary for identifying its impacts in the changing Arctic. This study assesses springtime snow conditions on Arctic sea ice using airborne snow thickness measurements from Operation IceBridge (2009-2012). The 2012 data were validated with coordinated in situ measurements taken in March 2012 during the BRomine, Ozone, and Mercury EXperiment field campaign. We find a statistically significant correlation coefficient of 0.59 and RMS error of 5.8 cm. The comparison between the IceBridge snow thickness product and the 1937, 1954-1991 Soviet drifting ice station data suggests that the snow cover has thinned by 33% in the western Arctic and 44% in the Beaufort and Chukchi Seas. A rudimentary estimation shows that a thinner snow cover in the Beaufort and Chukchi Seas translates to a mid-December surface heat flux as high as 81 W/m2 compared to 32 W/m2. The relationship between the 2009-2012 thinner snow depth distribution and later sea ice freeze-up is statistically significant, with a correlation coefficient of 0.59. These results may help us better understand the surface energy budget in the changing Arctic, and may improve our ability to predict the future state of the sea ice cover.

  15. Mapping of the air-sea CO2 flux in the Arctic Ocean and its adjacent seas: Basin-wide distribution and seasonal to interannual variability

    Science.gov (United States)

    Yasunaka, Sayaka; Murata, Akihiko; Watanabe, Eiji; Chierici, Melissa; Fransson, Agneta; van Heuven, Steven; Hoppema, Mario; Ishii, Masao; Johannessen, Truls; Kosugi, Naohiro; Lauvset, Siv K.; Mathis, Jeremy T.; Nishino, Shigeto; Omar, Abdirahman M.; Olsen, Are; Sasano, Daisuke; Takahashi, Taro; Wanninkhof, Rik

    2016-09-01

    We produced 204 monthly maps of the air-sea CO2 flux in the Arctic north of 60°N, including the Arctic Ocean and its adjacent seas, from January 1997 to December 2013 by using a self-organizing map technique. The partial pressure of CO2 (pCO2) in surface water data were obtained by shipboard underway measurements or calculated from alkalinity and total inorganic carbon of surface water samples. Subsequently, we investigated the basin-wide distribution and seasonal to interannual variability of the CO2 fluxes. The 17-year annual mean CO2 flux shows that all areas of the Arctic Ocean and its adjacent seas were net CO2 sinks. The estimated annual CO2 uptake by the Arctic Ocean was 180 TgC yr-1. The CO2 influx was strongest in winter in the Greenland/Norwegian Seas (>15 mmol m-2 day-1) and the Barents Sea (>12 mmol m-2 day-1) because of strong winds, and strongest in summer in the Chukchi Sea (∼10 mmol m-2 day-1) because of the sea-ice retreat. In recent years, the CO2 uptake has increased in the Greenland/Norwegian Sea and decreased in the southern Barents Sea, owing to increased and decreased air-sea pCO2 differences, respectively.

  16. Severe winter weather as a response to the lowest Arctic sea-ice anomalies

    Institute of Scientific and Technical Information of China (English)

    CHEN Hongxia; LIU Na; ZHANG Zhanhai

    2013-01-01

    Possible impact of reduced Arctic sea-ice on winter severe weather in China is investigated regarding the snowstorm over southern China in January 2008. The sea-ice conditions in the summer (July-September) and fall (September-November) of 2007 show that the sea-ice is the lowest that year. During the summer and fall of 2007, sea ice displayed a significant decrease in the East Siberian, the northern Chukchi Sea, the western Beaufort Sea, the Barents Sea, and the Kara Sea. A ECHAM5.4 atmospheric general circula-tion model is forced with realistic sea-ice conditions and strong thermal responses with warmer surface air temperature and higher-than-normal heat flux associated with the sea-ice anomalies are found. The model shows remote atmospheric responses over East Asia in January 2008, which result in severe snowstorm over southern China. Strong water-vapor transported from the Bay of Bengal and from the Pacific Ocean related to Arctic sea-ice anomalies in the fall (instead of summer) of 2007 is considered as one of the main causes of the snowstorm formation.

  17. APL-UW Deep Water Propagation: Philippine Sea Signal Physics and North Pacific Ambient Noise

    Science.gov (United States)

    2015-10-15

    oceans (Dyer 1988, Roth et al. 2012). www.annualreviews.org • Sounds in the Ocean at 1–100 Hz 125 A nn u. R ev . M ar in e. S ci . 2 01 4. 6: 11 7...Acoust. Bull. 18:5–8 Roth E, Hildebrand J, Wiggins S, Ross D. 2012. Underwater ambient noise on the Chukchi Sea continental slope from 2006–2009. J...Thurstan, R.H., and C.M. Roberts. 2010. Ecological Meltdown in the Firth of Clyde, Scotland : Two Centuries of Change in a Coastal Marine Ecosystem. PLoS ONE

  18. Petrography and U-Pb zircon geochronology of Caledonian age orthogneisses dredged from the Chukchi Borderland, Arctic Ocean

    Science.gov (United States)

    Brumley, K.; Miller, E. L.; Mayer, L. A.; Wooden, J. L.; Dumitru, T. A.

    2011-12-01

    The Caledonian orogenic belt developed in the Ordovician to Devonian affecting northern Europe, Greenland and Arctic Canada. Caledonian deformational trends continue into the Arctic region disappearing at the rifted margin of the Arctic Ocean. Syn-orogenic magmatism in the Barents region date deformation of Grenvillian basement during the Caledonian event to be between about 450-410 Ma (Johansson et al., 2005; Gee et al., 2006; Gee and Tebenkov, 2004). Over 500 kilos of metamorphic rock was dredged from outcrops in the central Chukchi Borderland in 2009 (HLY0905) that included amphibolites and orthogneisses metamorphosed to amphibolite facies continuing to deform under greenschist conditions. Zircons were separated from two orthogneiss samples from this dredge, and single grain zircon U-Pb ages were determined by SHRIMP analysis be 428 Ma ± 3.4 for both samples (N=60). One sample had several zircon grains with distinct igneous cores that ranged in age from about 850-1000 Ma. Grenville age plutons (1000-910 Ma) that were later involved in Caledonian deformation and intruded by 450-410 Ma aged plutons are found on western and eastern Svalbard (Johansson et al., 2005), eastern Greenland, and the Pearya Terrane of northern Ellesmere Island (Trettin,1986, 1992). The Franklinian basement of Arctic Alaska and Canada do not share these Grenvillian ages (Trentin et al, 1987). This suggests that the inherited zircon cores in the Chukchi Borderland orthogneisses were derived, at least in part, from an older Grenvillian basement like that of Pearya, Svalbard and parts of Greenland and later intruded by Caledonian aged granites.

  19. The role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jinlun; MI ke Steele; Rebecca Woodgate

    2008-01-01

    A model study is conducted to examine the role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007. The model generally agrees with the observations in showing considerable seasonal and intcrannual variability of the Pacific water inflow at Bering Strait in response to changes in atmospheric circulation.During summer 2007 anomalously strong southerly winds over the Pacific sector of the Arctic Ocean strengthen the ocean circulation and bring more Pacific water into the Arctic than the recent (2000-2006) average. The simulated summer (3 months )2007 mean Pacific water inflow at Bering Strait is 1.2 Sv, which is the highest in the past three decades of the simulation and is 20% higher than the recent average. Particularly, the Pacific water inflow in September 2007 is about 0.5 Sv or 50% above the 2000-2006 average. The strengthened warm Pacific water inflow carries an additional 1.0 × 1020 Joules of heat into the Arctic, enough to melt an additional 0. 5 m of ice over the whole Chukchi Sea. In the model the extra summer oceanic heat brought in by the Pacific water mainly stays in the Chukchi and Beaufort region, contributing to the wanning of surface waters in that region. The heat is in constant contact with the ice cover in the region in July through September. Thus the Pacific water plays a role in ice melting in the Chukchi and Beaufort region all summer long in 2007, likely contributing to up to 0.5 m per month additional ice melting in some area of that region.

  20. The footprints of 16 year trends of Arctic springtime cloud and radiation properties on September sea ice retreat

    Science.gov (United States)

    Huang, Yiyi; Dong, Xiquan; Xi, Baike; Dolinar, Erica K.; Stanfield, Ryan E.

    2017-02-01

    The most prominent September Arctic sea ice decline over the period of 2000-2015 occurs over the Siberian Sea, Laptev Sea, and Kara Sea. The satellite observed and retrieved sea ice concentration (SIC) and cloud/radiation properties over the Arctic (70°-90°N) have been used to investigate the impact of springtime cloud and radiation properties on September SIC variation. Positive trends of cloud fractions, cloud water paths, and surface downward longwave flux at the surface over the September sea ice retreat areas are found over the period of 1 March to 14 May, while negative trends are found over the period of 15 May to 28 June. The spatial distributions of correlations between springtime cloud/radiation properties and September SIC have been calculated, indicating that increasing cloud fractions and downward longwave flux during springtime tend to enhance sea ice melting due to strong cloud warming effect. Surface downward and upward shortwave fluxes play an important role from May to June when the onset of sea ice melting occurs. The comparison between linearly detrended and nondetrended of each parameter indicates that significant impact of cloud and radiation properties on September sea ice retreat occurs over the Chukchi/Beaufort Sea at interannual time scale, especially over the period of 31 March to 29 April, while strongest climatological trends are found over the Laptev/Siberian Sea.

  1. Kinematic History and Tectonic Evolution of the Amerasian Basin: Investigating Palaeo-Plate Boundaries around the Chukchi Borderlands

    Science.gov (United States)

    Brumley, K.; Coakley, B.; Stone, D.; Wallace, W.

    2007-12-01

    The multi-stage opening of the Arctic Ocean's Amerasian Basin is only partially understood due to the difficulty of utilizing traditional marine geologic and geophysical techniques in ice-covered waters. While the kinematic development of the Eurasian Basin is well-understood to be the northernmost extension of the Mid-Atlantic Ridge, the history of the morphologically complex Amerasian Basin may be due to multiple events, significantly complicating interpretation of its history. Any detailed model for the opening of the Amerasian Basin must both incorporate structures that accommodate spreading as well as explain the tectonic mechanisms that drove basin development. Cretaceous-age tholeiitic flood basalts and associated radiating dike swarms of the High Arctic Large Igneous Province (HALIP), found along the basin margin, provide a tectonic mechanism and geometry to substantiate sound reconstruction. Detailed models need also consider pre-existing zones of weakness such as the deformation front of the Devonian Caledonides, which may underlie Barents Shelf sediments (Gee and Bogolepova, 2003). Reactivation of these ancient structural trends along this suture zone may explain the motion of Mendeleev Ridge as it rifted from Lomonosov Ridge and created the rectangular pull-apart basin between them. We propose a revised plate model for the development of the Amerasian Basin. A Cretaceous magmatic source localized under the Alpha Ridge accompanied the onset of rifting. This generated the HALIP radiating dike swarms and tholeiitic flood basalts found on the DeLong Islands, Svalbard, Franz Joseph Land, Greenland, Sverdrup Basin and, possibly, the Alpha and Mendeleev Ridges. New bathymetric and sub-bottom profiling data also suggests the existence of igneous dikes on Chukchi Cap. The subsequent development of a triple junction resulted in dilational opening of the Canada Basin. Spreading was accommodated by the migration of the southern edges of the northeastern Siberian

  2. Arctic and Antarctic Sea Ice Changes and Impacts (Invited)

    Science.gov (United States)

    Nghiem, S. V.

    2013-12-01

    The extent of springtime Arctic perennial sea ice, important to preconditioning summer melt and to polar sunrise photochemistry, continues its precipitous reduction in the last decade marked by a record low in 2012, as the Bromine, Ozone, and Mercury Experiment (BROMEX) was conducted around Barrow, Alaska, to investigate impacts of sea ice reduction on photochemical processes, transport, and distribution in the polar environment. In spring 2013, there was further loss of perennial sea ice, as it was not observed in the ocean region adjacent to the Alaskan north coast, where there was a stretch of perennial sea ice in 2012 in the Beaufort Sea and Chukchi Sea. In contrast to the rapid and extensive loss of sea ice in the Arctic, Antarctic sea ice has a trend of a slight increase in the past three decades. Given the significant variability in time and in space together with uncertainties in satellite observations, the increasing trend of Antarctic sea ice may arguably be considered as having a low confidence level; however, there was no overall reduction of Antarctic sea ice extent anywhere close to the decreasing rate of Arctic sea ice. There exist publications presenting various factors driving changes in Arctic and Antarctic sea ice. After a short review of these published factors, new observations and atmospheric, oceanic, hydrological, and geological mechanisms contributed to different behaviors of sea ice changes in the Arctic and Antarctic are presented. The contribution from of hydrologic factors may provide a linkage to and enhance thermal impacts from lower latitudes. While geological factors may affect the sensitivity of sea ice response to climate change, these factors can serve as the long-term memory in the system that should be exploited to improve future projections or predictions of sea ice changes. Furthermore, similarities and differences in chemical impacts of Arctic and Antarctic sea ice changes are discussed. Understanding sea ice changes and

  3. Critical Mechanisms for the Formation of Extreme Arctic Sea-Ice Extent in the Summers of 2007 and 1996

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xiquan [Beijing Normal Univ. (China); Univ. of North Dakota, Grand Forks, ND (United States); Zib, Benjamin J. [Univ. of North Dakota, Grand Forks, ND (United States); Xi, Baike [Univ. of North Dakota, Grand Forks, ND (United States); Stanfield, Ryan [Univ. of North Dakota, Grand Forks, ND (United States); Deng, Yi [Georgia Inst. of Technology, Atlanta, GA (United States); Zhang, Xiangdong [Univ. of Alaska, Fairbanks, AK (United States); Lin, B. [NASA Langley Research Center, Hampton, VA (United States); Long, Charles N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-08-29

    A warming Arctic climate is undergoing significant e 21 nvironmental change, most evidenced by the reduction of Arctic sea-ice extent during the summer. In this study, we examine two extreme anomalies of September sea-ice extent in 2007 and 1996, and investigate the impacts of cloud fraction (CF), atmospheric precipitable water vapor (PWV), downwelling longwave flux (DLF), surface air temperature (SAT), pressure and winds on the sea-ice variation in 2007 and 1996 using both satellite-derived sea-ice products and MERRA reanalysis. The area of the Laptev, East Siberian and West Chukchi seas (70-90oN, 90-180oE) has experienced the largest variation in sea-ice extent from year-to-year and defined here as the Area Of Focus (AOF). The record low September sea-ice extent in 2007 was associated with positive anomalies 30 of CF, PWV, DLF, and SAT over the AOF. Persistent anti-cyclone positioned over the Beaufort Sea coupled with low pressure over Eurasia induced easterly zonal and southerly meridional winds. In contrast, negative CF, PWV, DLF and SAT anomalies, as well as opposite wind patterns to those in 2007, characterized the 1996 high September sea-ice extent. Through this study, we hypothesize the following positive feedbacks of clouds, water vapor, radiation and atmospheric variables on the sea-ice retreat during the summer 2007. The record low sea-ice extent during the summer 2007 is initially triggered by the atmospheric circulation anomaly. The southerly winds across the Chukchi and East Siberian seas transport warm, moist air from the north Pacific, which is not only enhancing sea-ice melt across the AOF, but also increasing clouds. The positive cloud feedback results in higher SAT and more sea-ice melt. Therefore, 40 more water vapor could be evaporated from open seas and higher SAT to form more clouds, which will enhance positive cloud feedback. This enhanced positive cloud feedback will then further increase SAT and accelerate the sea-ice retreat during the

  4. Duration of the Arctic sea ice melt season: Regional and interannual variability, 1979-2001

    Science.gov (United States)

    Belchansky, G.I.; Douglas, D.C.; Platonov, N.G.

    2004-01-01

    Melt onset dates, freeze onset dates, and melt season duration were estimated over Arctic sea ice, 1979–2001, using passive microwave satellite imagery and surface air temperature data. Sea ice melt duration for the entire Northern Hemisphere varied from a 104-day minimum in 1983 and 1996 to a 124-day maximum in 1989. Ranges in melt duration were highest in peripheral seas, numbering 32, 42, 44, and 51 days in the Laptev, Barents-Kara, East Siberian, and Chukchi Seas, respectively. In the Arctic Ocean, average melt duration varied from a 75-day minimum in 1987 to a 103-day maximum in 1989. On average, melt onset in annual ice began 10.6 days earlier than perennial ice, and freeze onset in perennial ice commenced 18.4 days earlier than annual ice. Average annual melt dates, freeze dates, and melt durations in annual ice were significantly correlated with seasonal strength of the Arctic Oscillation (AO). Following high-index AO winters (January–March), spring melt tended to be earlier and autumn freeze later, leading to longer melt season durations. The largest increases in melt duration were observed in the eastern Siberian Arctic, coincident with cyclonic low pressure and ice motion anomalies associated with high-index AO phases. Following a positive AO shift in 1989, mean annual melt duration increased 2–3 weeks in the northern East Siberian and Chukchi Seas. Decreasing correlations between consecutive-year maps of melt onset in annual ice during 1979–2001 indicated increasing spatial variability and unpredictability in melt distributions from one year to the next. Despite recent declines in the winter AO index, recent melt distributions did not show evidence of reestablishing spatial patterns similar to those observed during the 1979–88 low-index AO period. Recent freeze distributions have become increasingly similar to those observed during 1979–88, suggesting a recurrent spatial pattern of freeze chronology under low-index AO conditions.

  5. Biases of the Arctic climate in a regional ocean-sea ice-atmosphere coupled model:an annual validation

    Institute of Scientific and Technical Information of China (English)

    LIU Xiying

    2014-01-01

    The Coupling of three model components, WRF/PCE (polar climate extension version of weather research and forecasting model ( WRF)), ROMS (regional ocean modeling system), and CICE (community ice code), has been implemented, and the regional atmosphere-ocean-sea ice coupled model named WRF/PCE-ROMS-CICE has been validated against ERA-interim reanalysis data sets for 1989. To better understand the reasons that generate model biases, the WRF/PCE-ROMS-CICE results were compared with those of its components, the WRF/PCE and the ROMS-CICE. There are cold biases in surface air temperature (SAT) over the Arctic Ocean, which contribute to the sea ice concentration (SIC) and sea surface temperature (SST) biases in the results of the WRF/PCE-ROMS-CICE. The cold SAT biases also appear in results of the atmo-spheric component with a mild temperature in winter and similar temperature in summer. Compared to results from the WRF/PCE, due to influences of different distributions of the SIC and the SST and inclusion of interactions of air-sea-sea ice in the WRF/PCE-ROMS-CICE, the simulated SAT has new features. These influences also lead to apparent differences at higher levels of the atmosphere, which can be thought as responses to biases in the SST and sea ice extent. There are similar atmospheric responses in feature of distribution to sea ice biases at 700 and 500 hPa, and the strength of responses weakens when the pressure decreases in January. The atmospheric responses in July reach up to 200 hPa. There are surplus sea ice ex-tents in the Greenland Sea, the Barents Sea, the Davis Strait and the Chukchi Sea in winter and in the Beau-fort Sea, the Chukchi Sea, the East Siberian Sea and the Laptev Sea in summer in the ROMS-CICE. These differences in the SIC distribution can all be explained by those in the SST distributions. These features in the simulated SST and SIC from ROMS-CICE also appear in the WRF/PCE-ROMS-CICE. It is shown that the performance of the WRF/PCE-ROMS-CICE is

  6. Physical characteristics of summer sea ice across the Arctic Ocean

    Science.gov (United States)

    Tucker, W. B.; Gow, A.J.; Meese, D.A.; Bosworth, H.W.; Reimnitz, E.

    1999-01-01

    Sea ice characteristics were investigated during July and August on the 1994 transect across the Arctic Ocean. Properties examined from ice cores included salinity, temperature, and ice structure. Salinities measured near zero at the surface, increasing to 3-4??? at the ice-water interface. Ice crystal texture was dominated by columnar ice, comprising 90% of the ice sampled. Surface albedos of various ice types, measured with radiometers, showed integrated shortwave albedos of 0.1 to 0.3 for melt ponds, 0.5 for bare, discolored ice, and 0.6 to 0.8 for a deteriorated surface or snow-covered ice. Aerial photography was utilized to document the distribution of open melt ponds, which decreased from 12% coverage of the ice surface in late July at 76??N to almost none in mid-August at 88??N. Most melt ponds were shallow, and depth bore no relationship to size. Sediment was pervasive from the southern Chukchi Sea to the north pole, occurring in bands or patches. It was absent in the Eurasian Arctic, where it had been observed on earlier expeditions. Calculations of reverse trajectories of the sediment-bearing floes suggest that the southernmost sediment was entrained during ice formation in the Beaufort Sea while more northerly samples probably originated in the East Siberian Sea, some as far west as the New Siberian Islands.

  7. Isolation of novel psychrophilic bacteria from Arctic sea ice

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The phylogenetic diversity of culturable psychrophilic bacteria associated with sea ice from the high latitude regions of Canadian Basin and Chukchi Sea, Arctic, was investigated. A total of 34 psychropilic strains were isolated using three methods of (Ⅰ) dilution plating (at 4 ℃), (Ⅱ) bath culturing (at -1 ℃) and dilution plating, and (Ⅲ) cold shock (-20 ℃ for 24 h), bath culturing and dilution plating under aerobic conditions. Sea-ice samples were exposed to -20 ℃ for 24 h that might reduce the number of common microorganisms and encourage outgrowth of psychrophilic strains. This process might be able to be introduced to isolation psychrophilic bacteria from other environmental samples in future study. 16S rDNA nearly full-length sequence analysis revealed that psychrophilic strains felled in two phylogenetic divisions, γ-proteobacteria (in the genera Colwellia、Marinobacter、Shewanella、Glaciecola、Marinomonas and Pseudoalteromonas) and Cytophaga-Flexibacter-Bacteroides (Flavobacterium and Psychroflexus). Fifteen of bacterial isolates quite likely represented novel species (16S rDNA sequence similarity below 98%). One of strains (BSi20002) from Canadian Basin showed 100% sequence similarity to that of Marinobacter sp. ANT8277 isolated from the Antarctic Weddell sea ice, suggesting bacteria may have a bipolar distribution at the species level.

  8. Phytoplankton distribution in unusually low sea ice cover over the Pacific Arctic

    Directory of Open Access Journals (Sweden)

    P. Coupel

    2012-11-01

    Full Text Available A large part of the Pacific Arctic basin experiences ice-free conditions in summer as a result of sea ice cover steadily decreasing over the last decades. To evaluate the impact of sea ice retreat on the marine ecosystem, phytoplankton in situ observations were acquired over the Chukchi shelf and the Canadian basin in 2008, a year of high melting. Pigment analyses and taxonomy enumerations were used to characterise the distribution of main phytoplanktonic groups. Marked spatial variability of the phytoplankton distribution was observed in summer 2008. Comparison of eight phytoplankton functional groups and 3 size-classes (pico-, nano- and micro-phytoplankton also showed significant differences in abundance, biomass and distribution between summer of low ice cover (2008 and heavy ice summer (1994. Environmental parameters such as freshening, stratification, light and nutrient availability are discussed as possible causes to explain the observed differences in phytoplankton community structure between 1994 and 2008.

  9. Change of sea ice content in the Arctic and the associated climatic effects: detection and simulation

    Directory of Open Access Journals (Sweden)

    I. I. Mokhov

    2013-01-01

    Full Text Available Modeling results of the impact of sea surface temperature and sea ice extent changes over the last decades on the formation of weather and climate anomalies are presented. It was found that the Arctic sea ice area reduction may lead to anti-cyclonic regimes’ formation causing anomalously cold winters in particular on the Russian territory. Using simulation with an atmospheric general circulation model, it is shown that the Early 20th Century Warming must have been accompanied by a large negative Arctic sea ice area anomaly in winter time. The results imply a considerable role of long-term natural climate variations in the modern sea ice area decrease. Estimates of the possible probability’s changes of the dangerous events of strong winds and high waves in the Arctic basin and favorable navigation conditions for the Northern Sea Route in the 21st century are made based on numerical model calculations. An increase of extreme wave height is found to the middle of the 21st century for Kara and Chukchi Seas as a consequence of prolonged run length and increased surface winds.

  10. Quartz-sericite and argillic alterations at the Peschanka Cu-Mo-Au deposit, Chukchi Peninsula, Russia

    Science.gov (United States)

    Marushchenko, L. I.; Baksheev, I. A.; Nagornaya, E. V.; Chitalin, A. F.; Nikolaev, Yu. N.; Kal'ko, I. A.; Prokofiev, V. Yu.

    2015-05-01

    The porphyry Peschanka copper-molybdenum-gold deposit and the Nakhodka ore field located in the Baimka ore trend on the western Chukchi Peninsula are spatially related to monzonitic rocks of the Early Cretaceous Egdykgych Complex. Two types of quartz-sericite metasomatic rocks (QSR) have been identified at both the deposits and the ore field: (I) chlorite-quartz-muscovite rock with bornite and chalcopyrite (porphyry type) and (II) tourmaline-quartz-carbonate-muscovite ± phengite rock accompanied by veins with base-metal mineralization (subepithermal or transitional type), as well as carbonate-quartz-illite rock (argillic alteration) accompanied by veins with precious metal mineralization (epithermal type). The QSR I chlorite evolves from chamosite to clinochlore, which is caused by increasing H2S activity in mineralizing fluid and precipitation of sulfide minerals. The QSR I clinochlore is significantly depleted in silica as compared with that from the rocks affected by argillic alteration. The chemical composition of muscovite from both quartz-sericite alterations is similar. The QSR II carbonates evolve from calcite through dolomite to siderite, which results from the increasing activity of CO2 followed by the decreasing activity of H2S in mineralizing fluid. The Mn content in dolomite is similar to that in beresite (quartz-muscovite-carbonate-pyrite metasomatic rock) of the intrusion-related gold deposits. Illite from argillic alteration is depleted in Al as compared with that of postvolcanic epithermal Au-Ag deposits. However, carbonates from the discussed argillic alteration rhodochrosite and Mn-rich dolomite are similar to those from quartz-illite rock at postvolcanic epithermal Au-Ag deposits.

  11. Concentration and distribution of 17 organochlorine pesticides (OCPs) in seawater from the Japan Sea northward to the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Seventeen classic organochlorine pesticides in surface seawater were studied in terms of their composition pattern as well as their distribution pattern in the areas covering the Japan Sea,Okhotsk Sea,Bering Sea,Chukchi Sea and Arctic Ocean.Their concentrations varied,but roughly two levels were seen with one ranging between 0.1 and 1 ng L-1 for most HCH isomers and the other lower than 0.1 ng L-1 for other chemicals.Of the 17 target compounds,HCHs were dominant with a total concentration percentage generally more than 50%,and a relatively high concentration percentage of heptachlor and aldrine was also observed at scattered stations.The historical long-term trend of several target chemicals in the five sea zones considered was discussed in comparison with previous reports.Inter-sea zone comparison was carried out for individual chemicals by comparing the concentration variation in all five sea zones.A higher variation in concentration was generally found in the northern sea zones,namely the Bering Sea,Chukchi Sea and Arctic Ocean,for most target compounds.The sum concentration of the 17 target chemicals displayed a general trend of increasing northward from the Japan Sea to the Okhotsk Sea to the Bering Sea to the Arctic Ocean.Different latitudinal trends were found forγ-HCH andγ-HCH,and the reason of this difference was discussed by considering their divergence of thermodynamic properties,which could contribute to a slightly different fractionation effect during their northward transport driven by atmospheric long range transport.The source of the HCHs was identified by analyzing theγ-HCH/γ-HCH ratio,which was less than 4 without exception,indicating a component characteristic featuring a mixture of technical HCHs and lindane.In addition,the vertical distribution ofγ-HCH,γ-HCH and their ratio at station B80 was discussed.Different patterns were found in the upper 300 m while in layers from 300 m downward to 3500 m the patterns were fairly comparable

  12. Arctic sea-ice ridges—Safe heavens for sea-ice fauna during periods of extreme ice melt?

    Science.gov (United States)

    Gradinger, Rolf; Bluhm, Bodil; Iken, Katrin

    2010-01-01

    The abundances and distribution of metazoan within-ice meiofauna (13 stations) and under-ice fauna (12 stations) were investigated in level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin in June/July 2005 using a combination of ice coring and SCUBA diving. Ice meiofauna abundance was estimated based on live counts in the bottom 30 cm of level sea ice based on triplicate ice core sampling at each location, and in individual ice chunks from ridges at four locations. Under-ice amphipods were counted in situ in replicate ( N=24-65 per station) 0.25 m 2 quadrats using SCUBA to a maximum water depth of 12 m. In level sea ice, the most abundant ice meiofauna groups were Turbellaria (46%), Nematoda (35%), and Harpacticoida (19%), with overall low abundances per station that ranged from 0.0 to 10.9 ind l -1 (median 0.8 ind l -1). In level ice, low ice algal pigment concentrations (3 m where abundances were up to 42-fold higher compared with level ice. We propose that the summer ice melt impacted meiofauna and under-ice amphipod abundance and distribution through (a) flushing, and (b) enhanced salinity stress at thinner level sea ice (less than 3 m thickness). We further suggest that pressure ridges, which extend into deeper, high-salinity water, become accumulation regions for ice meiofauna and under-ice amphipods in summer. Pressure ridges thus might be crucial for faunal survival during periods of enhanced summer ice melt. Previous estimates of Arctic sea ice meiofauna and under-ice amphipods on regional and pan-Arctic scales likely underestimate abundances at least in summer because they typically do not include pressure ridges.

  13. Sedimentary organic matter variations in the Chukchi Borderland over the last 155 kyr

    Directory of Open Access Journals (Sweden)

    S. F. Rella

    2011-03-01

    Full Text Available Knowledge on past variability of sedimentary organic carbon in the Arctic Ocean is important to assess natural carbon cycling and transport processes related to global climate changes. However, the late Pleistocene oceanographic history of the Arctic is still poorly understood. In the present study we show sedimentary records of total organic carbon (TOC, C/N and CaCO3 from a piston core recovered from the northern Northwind Ridge in the far western Arctic Ocean, a region potentially sensitively responding to past variability in surface current regimes and sedimentary processes such as coastal erosion. An age model based on correlation of our CaCO3 record with the benthic δ18O stack, supplemented by lithological constraints, suggests that the piston core records paleoenvironmental changes of the last 155 kyr. According to this age model, TOC and C/N show orbital-scale increases and decreases that can be respectively correlated to the waxing and waning of large ice sheets dominating the Eurasian Arctic, suggesting advection of fine suspended matter derived from glacial erosion to the Northwind Ridge by eastward flowing intermediate water and/or surface water and sea ice during cold episodes of the last two glacial-interglacial cycles. At millennial scales, increases in TOC and C/N appear to correlate to a suite of Dansgaard-Oeschger Stadials between 120 and 40 ka before present (BP and thus seem to respond to abrupt northern hemispheric temperature changes. Between 65 and 40 ka BP, closures and openings of the Bering Strait could have additionally influenced TOC and C/N variability. CaCO3 content tends to anti-correlate with TOC and C/N on both orbital and millennial time scales, which we interpret as enhanced sediment advection from the carbonate-rich Canadian Arctic via an extended Beaufort Gyre during warm periods of the last two glacial-interglacial cycles and increased terrestrial organic carbon

  14. Invariant polar bear habitat selection during a period of sea ice loss.

    Science.gov (United States)

    Wilson, Ryan R; Regehr, Eric V; Rode, Karyn D; St Martin, Michelle

    2016-08-17

    Climate change is expected to alter many species' habitat. A species' ability to adjust to these changes is partially determined by their ability to adjust habitat selection preferences to new environmental conditions. Sea ice loss has forced polar bears (Ursus maritimus) to spend longer periods annually over less productive waters, which may be a primary driver of population declines. A negative population response to greater time spent over less productive water implies, however, that prey are not also shifting their space use in response to sea ice loss. We show that polar bear habitat selection in the Chukchi Sea has not changed between periods before and after significant sea ice loss, leading to a 75% reduction of highly selected habitat in summer. Summer was the only period with loss of highly selected habitat, supporting the contention that summer will be a critical period for polar bears as sea ice loss continues. Our results indicate that bears are either unable to shift selection patterns to reflect new prey use patterns or that there has not been a shift towards polar basin waters becoming more productive for prey. Continued sea ice loss is likely to further reduce habitat with population-level consequences for polar bears.

  15. Bowhead whale body condition and links to summer sea ice and upwelling in the Beaufort Sea

    Science.gov (United States)

    George, John C.; Druckenmiller, Matthew L.; Laidre, Kristin L.; Suydam, Robert; Person, Brian

    2015-08-01

    We examined the response of bowhead whale (Balaena mysticetus) body condition to summer sea ice conditions and upwelling-favorable winds. We used a long-term dataset collected from whales of the Bering-Chukchi-Beaufort Seas (BCB) stock to estimate various body condition indices (BCI's) for individual whales that were harvested by Alaskan Eskimos. A series of offshore regions frequented by bowhead whales in summer were delineated and used to quantify interannual summertime environmental conditions including: (a) mean open water fraction, (b) duration of melt season, (c) date of continuous freeze-up, and (d) mean upwelling-favorable wind stress. Body condition was analyzed relative to these metrics for both the preceding summer feeding season and the previous three seasons combined. Our analysis indicates a significant increase in the long-term trend in an axillary girth-based body condition index (BCIG) over the study period (1989-2011). The increase in BCIG is likely associated with the trend in overall reduction of sea ice, including increased duration of open water, changes in upwelling potential (wind stress), and possibly higher primary production in the Pacific Arctic marine ecosystem favoring water-column invertebrates. We found strong significant positive correlations between BCIG and late summer open water fraction in the Beaufort Sea and smaller nearshore areas off the Mackenzie Delta and west of Banks Island. Additionally, BCIG was positively and significantly correlated with duration of melt season, later date of freeze-up in the Beaufort Sea, and upwelling-favorable winds on the Mackenzie shelf and west of Banks Island. A strong seasonal difference in BCI's was noted for subadult bowheads, presumably associated with summer feeding; however, yearlings were found to drop in BCI over at least the first summer after weaning. Our results indicate an overall increase in bowhead whale body condition and a positive correlation with summer sea ice loss over the

  16. Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water

    Science.gov (United States)

    2014-01-01

    Polar bears (Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movement data from 52 adult female polar bears wearing Global Positioning System (GPS) collars, including some with dependent young, to document long-distance swimming (>50 km) by polar bears in the southern Beaufort and Chukchi seas. During 6 years (2004-2009), we identified 50 long-distance swims by 20 bears. Swim duration and distance ranged from 0.7 to 9.7 days (mean = 3.4 days) and 53.7 to 687.1 km (mean = 154.2 km), respectively. Frequency of swimming appeared to increase over the course of the study. We show that adult female polar bears and their cubs are capable of swimming long distances during periods when extensive areas of open water are present. However, long-distance swimming appears to have higher energetic demands than moving over sea ice. Our observations suggest long-distance swimming is a behavioral response to declining summer sea-ice conditions.

  17. Arctic sea ice a major determinant in Mandt's black guillemot movement and distribution during non-breeding season.

    Science.gov (United States)

    Divoky, G J; Douglas, D C; Stenhouse, I J

    2016-09-01

    Mandt's black guillemot (Cepphus grylle mandtii) is one of the few seabirds associated in all seasons with Arctic sea ice, a habitat that is changing rapidly. Recent decreases in summer ice have reduced breeding success and colony size of this species in Arctic Alaska. Little is known about the species' movements and distribution during the nine month non-breeding period (September-May), when changes in sea ice extent and composition are also occurring and predicted to continue. To examine bird movements and the seasonal role of sea ice to non-breeding Mandt's black guillemots, we deployed and recovered (n = 45) geolocators on individuals at a breeding colony in Arctic Alaska during 2011-2015. Black guillemots moved north to the marginal ice zone (MIZ) in the Beaufort and Chukchi seas immediately after breeding, moved south to the Bering Sea during freeze-up in December, and wintered in the Bering Sea January-April. Most birds occupied the MIZ in regions averaging 30-60% sea ice concentration, with little seasonal variation. Birds regularly roosted on ice in all seasons averaging 5 h d(-1), primarily at night. By using the MIZ, with its roosting opportunities and associated prey, black guillemots can remain in the Arctic during winter when littoral waters are completely covered by ice.

  18. Fracture of summer perennial sea ice by ocean swell as a result of Arctic storms

    Science.gov (United States)

    Asplin, Matthew G.; Galley, Ryan; Barber, David G.; Prinsenberg, Simon

    2012-06-01

    The Arctic summer minimum sea ice extent has experienced a decreasing trend since 1979, with an extreme minimum extent of 4.27 × 106 km2 in September 2007, and a similar minimum in 2011. Large expanses of open water in the Siberian, Laptev, Chukchi, and Beaufort Seas result from declining summer sea ice cover, and consequently introduce long fetch within the Arctic Basin. Strong winds from migratory cyclones coupled with increasing fetch generate large waves which can propagate into the pack ice and break it up. On 06 September 2009, we observed the intrusion of large swells into the multiyear pack ice approximately 250 km from the ice edge. These large swells induced nearly instantaneous widespread fracturing of the multiyear pack ice, reducing the large, (>1 km diameter) parent ice floes to small (100-150 m diameter) floes. This process increased the total ice floe perimeter exposed to the open ocean, allowing for more efficient distribution of energy from ocean heat fluxes, and incoming radiation into the floes, thereby enhancing lateral melting. This process of sea ice decay is therefore presented as a potential positive feedback process that will accelerate the loss of Arctic sea ice.

  19. Pacific walrus (Odobenus rosmarus divergens resource selection in the Northern Bering Sea.

    Directory of Open Access Journals (Sweden)

    Chadwick V Jay

    Full Text Available The Pacific walrus is a large benthivore with an annual range extending across the continental shelves of the Bering and Chukchi Seas. We used a discrete choice model to estimate site selection by adult radio-tagged walruses relative to the availability of the caloric biomass of benthic infauna and sea ice concentration in a prominent walrus wintering area in the northern Bering Sea (St. Lawrence Island polynya in 2006, 2008, and 2009. At least 60% of the total caloric biomass of dominant macroinfauna in the study area was composed of members of the bivalve families Nuculidae, Tellinidae, and Nuculanidae. Model estimates indicated walrus site selection was related most strongly to tellinid bivalve caloric biomass distribution and that walruses selected lower ice concentrations from the mostly high ice concentrations that were available to them (quartiles: 76%, 93%, and 99%. Areas with high average predicted walrus site selection generally coincided with areas of high organic carbon input identified in other studies. Projected decreases in sea ice in the St. Lawrence Island polynya and the potential for a concomitant decline of bivalves in the region could result in a northward shift in the wintering grounds of walruses in the northern Bering Sea.

  20. Relating Regional Arctic Sea Ice and climate extremes over Europe

    Science.gov (United States)

    Ionita-Scholz, Monica; Grosfeld, Klaus; Lohmann, Gerrit; Scholz, Patrick

    2016-04-01

    The potential increase of temperature extremes under climate change is a major threat to society, as temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy. Hence, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation and sea ice concentration, is of major importance. At the same time, the decline in Arctic sea ice cover during the last 30 years has been widely documented and it is clear that this change is having profound impacts at regional as well as planetary scale. As such, this study aims to investigate the relation between the autumn regional sea ice concentration variability and cold winters in Europe, as identified by the numbers of cold nights (TN10p), cold days (TX10p), ice days (ID) and consecutive frost days (CFD). We analyze the relationship between Arctic sea ice variation in autumn (September-October-November) averaged over eight different Arctic regions (Barents/Kara Seas, Beaufort Sea, Chukchi/Bering Seas, Central Arctic, Greenland Sea, Labrador Sea/Baffin Bay, Laptev/East Siberian Seas and Northern Hemisphere) and variations in atmospheric circulation and climate extreme indices in the following winter season over Europe using composite map analysis. Based on the composite map analysis it is shown that the response of the winter extreme temperatures over Europe is highly correlated/connected to changes in Arctic sea ice variability. However, this signal is not symmetrical for the case of high and low sea ice years. Moreover, the response of temperatures extreme over Europe to sea ice variability over the different Arctic regions differs substantially. The regions which have the strongest impact on the extreme winter temperature over Europe are: Barents/Kara Seas, Beaufort Sea, Central Arctic and the Northern Hemisphere. For the years of high sea ice concentration in the Barents/Kara Seas there is a reduction in the number

  1. Field measurement of local ice pressures on the ARAON in the Beaufort Sea

    Directory of Open Access Journals (Sweden)

    Lee Tak-Kee

    2014-12-01

    Full Text Available This study conducted four field measurements of local ice pressure during the icebreaking voyage of the icebreaking research vessel “ARAON” in the Chukchi and Beaufort seas from July to August of 2010. For measurements, 14 strain gauges, including 8 strain gauge rosettes, were set on the bow of the port side. Influence coefficients were determined using a finite element model of the instrumented area and they were used to convert the measured strains on the hull structure to local ice pressures. The converted maximum pressure was calculated as 2.12 MPa on an area of 0.28 m2. Pressure-area curves were developed from the surveyed pressure data and the results were compared with previously measured data. The study results are expected to provide an understanding of local ice pressures and thus be useful in the structural design of ice class ships.

  2. WATER TEMPERATURE and Other Data from DRIFTING PLATFORM From Chukchi Sea - NW Coast of Alaska from 19811219 to 19820101 (NODC Accession 8500079)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data were collected by Flow Industries, Inc. under contract number 03-78-B01-61 to NOAA . The data are primarily from drifting ice buoys and were collected in...

  3. Bowhead Whale Feeding Ecology Study (BOWFEST): Aerial Survey in Chukchi and Beaufort Seas conducted from 2007-08-23 to 2011-09-16 (NCEI Accession 0131425)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bowhead Whale Feeding Ecology Study (BOWFEST) was initiated in May 2007 through an Interagency Agreement between the Bureau of Ocean Energy Management (BOEM)...

  4. AFSC/NMML Location-only satellite telemetry data for gray whales in the Bering and Chukchi Sea, 2012-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ARGOS location data (latitude and longitude in decimal format) and associated time (date and time) and location quality (as defined by Argos...

  5. MIZMAS: Modeling the Evolution of Ice Thickness and Floe Size Distributions in the Marginal Ice Zone of the Chukchi and Beaufort Seas

    Science.gov (United States)

    2013-09-30

    collaborated with Dr. G. Schmidt and the Goddard Institute for Space Studies (GISS) climate model development team for improving the GISS ModelE2... Model Intercomparison Project (CMIP5) archive for the IPCC Fifth Assessment Report (AR5). The work to contribute to AR5 has resulted in three...necessity of introducing FSD into the model to better simulate lateral ice melt in the region . We conducted a model study to quantify the impact of an

  6. AFSC/REFM: Groundfish Survey of the Chukchi Sea in 2013 by Shelf Habitat and Ecology of Fish and Zooplankton (SHELFZ)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Alaska Fisheries Science Centers (AFSC) Status of Stocks and Multispecies Assessment (SSMA) Programs Fishery Interaction Team (FIT) conducted an offshore fish...

  7. The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea

    DEFF Research Database (Denmark)

    Pearce, C.; Varhelyi, A.; Wastegård, S.

    2016-01-01

    to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset ΔR = 477 ± 60 years. This relatively high value may be explained...... and Greenland. This large geographic distribution combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid – late Holocene sediment...... reservoir age offset, is the first of its kind in the Arctic Ocean and provides an important framework for improving chronologies and correlating marine sediment archives in this region. Core 2PC has a high sediment accumulation rate averaging 200 cm/kyr throughout the last 4000 years, and the chronology...

  8. Ecosystem monitoring information collected in Hanna Shoal in the Chukchi Sea for the COMIDA CAB project from August 2012 to August 2013 (NODC Accession 0123220)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains physical, chemical, and biological data collected during research cruises for the Hanna Shoal Ecosystem Study. The study occurred at 138...

  9. MIZMAS: Modeling the Evolution of Ice Thickness and Floe Size Distributions in the Marginal Ice Zone of the Chukchi and Beaufort Seas

    Science.gov (United States)

    2015-09-30

    11 Figure 4. A comparison of 2014 ocean temperature and salinity profiles between MIZMAS and ice- tethered profiler #79. The panel in the top...row shows the track of ITP79, the second row shows MIZMAS ocean temperature and salinity along the track, the third row shows ITP79 observations...efforts planned by the ONR MIZ research initiative. Meanwhile, we also uses the Pan- arctic Ice/ Ocean Modeling and Assimilation System (PIOMAS), a variant

  10. Aerial Surveys of Endangered Whales in the Northern Bering, Eastern Chukchi and Alaskan Beaufort Seas, 1983: with a Five Year Review, 1979-1983.

    Science.gov (United States)

    1984-06-01

    performance of pilots Bill Babcock, Bill Belinski, Mike Bratlie, Gary Candee, George Donovan, Dale Moore and Terry Small, and the OAS maintenance and...Lisburne, Alaska. Mar. Fish. Rev. 42(9-10): 46-51. 1980. Schell, DM, P3 Ziemann, DM Parrish, KH Danton , and EJ Brown. Food web and nutrient dynamics

  11. Periodic bowhead whale aerial surveys by the USDI/Minerals Management Service in the Bering, Chukchi and Beaufort Seas, April 1979 - October 2001 (NODC Accession 0001139)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  12. Arctic underwater noise transients from sea ice deformation: Characteristics, annual time series, and forcing in Beaufort Sea.

    Science.gov (United States)

    Kinda, G Bazile; Simard, Yvan; Gervaise, Cédric; Mars, Jérôme I; Fortier, Louis

    2015-10-01

    A 13-month time series of Arctic Ocean noise from the marginal ice zone of the Eastern Beaufort Sea is analyzed to detect under-ice acoustic transients isolated from ambient noise with a dedicated algorithm. Noise transients due to ice cracking, fracturing, shearing, and ridging are sorted out into three categories: broadband impulses, frequency modulated (FM) tones, and high-frequency broadband noise. Their temporal and acoustic characteristics over the 8-month ice covered period, from November 2005 to mid-June 2006, are presented and their generation mechanisms are discussed. Correlations analyses showed that the occurrence of these ice transients responded to large-scale ice motion and deformation rates forced by meteorological events, often leading to opening of large-scale leads at main discontinuities in the ice cover. Such a sequence, resulting in the opening of a large lead, hundreds by tens of kilometers in size, along the margin of landfast ice and multiyear ice plume in the Beaufort-Chukchi seas is detailed. These ice transients largely contribute to the soundscape properties of the Arctic Ocean, for both its ambient and total noise components. Some FM tonal transients can be confounded with marine mammal songs, especially when they are repeated, with periods similar to wind generated waves.

  13. Sea ice cover variability and river run-off in the western Laptev Sea (Arctic Ocean) since the last 18 ka

    Science.gov (United States)

    Hörner, T.; Stein, R.; Fahl, K.; Birgel, D.

    2015-12-01

    Multi-proxy biomarker measurements were performed on two sediment cores (PS51/154, PS51/159) with the objective reconstructing sea ice cover (IP25, brassicasterol, dinosterol) and river-runoff (campesterol, β-sitosterol) in the western Laptev Sea over the last 18 ka with unprecedented temporal resolution. The sea ice cover varies distinctly during the whole time period. The absence of IP25 during 18 and 16 ka indicate that the western Laptev Sea was mostly covered with permanent sea ice (pack ice). However, a period of temporary break-up of the permanent ice coverage occurred at c. 17.2 ka (presence of IP25). Very little river-runoff occurred during this interval. Decreasing terrigenous (riverine) input and synchronous increase of marine produced organic matter around 16 ka until 7.5 ka indicate the gradual establishment of a marine environment in the western Laptev Sea related to the onset of the post-glacial transgression of the shelf. Strong river run-off and reduced sea ice cover characterized the time interval between 15.2 and 12.9 ka, including the Bølling/Allerød warm period (14.7 - 12.9 ka). Moreover, the DIP25 Index (ratio of HBI-dienes and IP25) might document the presence of Atlantic derived water at the western Laptev Sea shelf area. A sudden return to severe sea ice conditions occurred during the Younger Dryas (12.9 - 11.6 ka). This abrupt climate change was observed in the whole circum-Arctic realm (Chukchi Sea, Bering Sea, Fram Strait and Laptev Sea). At the onset of the Younger Dryas, a distinct alteration of the ecosystem (deep drop in terrigenous and phytoplankton biomarkers) may document the entry of a giant freshwater plume, possibly relating to the Lake Agassiz outburst at 13 ka. IP25 concentrations increase and higher values of the PIP25 Index during the last 7 ka reflect a cooling of the Laptev Sea spring season. Moreover, a short-term variability of c. 1.5 thousand years occurred during the last 12 ka, most probably following Bond Cycles.

  14. Seasonal Changes in the Marine Production Cycles in Response to Changes in Arctic Sea Ice and Upper Ocean Circulation

    Science.gov (United States)

    Spitz, Y. H.; Ashjian, C. J.; Campbell, R. G.; Steele, M.; Zhang, J.

    2011-12-01

    Significant seasonal changes in arctic sea ice have been observed in recent years, characterized by unprecedented summer melt-back. As summer sea ice extent shrinks to record low levels, the peripheral seas of the Arctic Ocean are exposed much earlier to atmospheric surface heat flux, resulting in longer and warmer summers with more oceanic heat absorption. The changing seasonality in the arctic ice/ocean system will alter the timing, magnitude, duration, and pattern of marine production cycles by disrupting key trophic linkages and feedbacks in planktonic food webs. We are using a coupled pan-arctic Biology/Ice/Ocean Modeling and Assimilation System (BIOMAS) to investigate the changes in the patterns of seasonality in the arctic physical and biological system. Focus on specific regions of the Arctic, such as the Chukchi Sea, the Beaufort Sea and the adjacent central Arctic, reveals that changes in the timing of the spring bloom, its duration and the response of the secondary producers vary regionally. The major changes are, however, characterized by an earlier phytoplankton bloom and a slight increase of the biomass. In addition, the largest response in the secondary producers is seen in the magnitude of the microzooplankton concentration as well as in the period (early summer to late fall) over which the microzooplankton is present.

  15. Assessing trend and variation of Arctic sea-ice extent during 1979–2012 from a latitude perspective of ice edge

    Directory of Open Access Journals (Sweden)

    Wentao Xia

    2014-09-01

    Full Text Available Arctic sea-ice extent (in summer has been shrinking since the 1970s. However, we have little knowledge of the detailed spatial variability of this shrinking. In this study, we examine the (latitudinal ice extent along each degree of longitude, using the monthly Arctic ice index data sets (1979–2012 from the National Snow and Ice Data Center. Statistical analysis suggests that: (1 for summer months (July–October, there was a 34-year declining trend in sea-ice extent at most regions, except for the Canadian Arctic Archipelago, Greenland and Svalbard, with retreat rates of 0.0562–0.0898 latitude degree/year (or 6.26–10.00 km/year, at a significance level of 0.05; (2 for sea ice not geographically muted by the continental coastline in winter months (January–April, there was a declining trend of 0.0216–0.0559 latitude degree/year (2.40–6.22 km/year, at a significance level of 0.05. Regionally, the most evident sea-ice decline occurred in the Chukchi Sea from August to October, Baffin Bay and Greenland Sea from January to May, Barents Sea in most months, Kara Sea from July to August and Laptev Sea and eastern Siberian Sea in August and September. Trend analysis also indicates that: (1 the decline in summer ice extent became significant (at a 0.05 significance level since 1999 and (2 winter ice extent showed a clear changing point (decline around 2000, becoming statistically significant around 2005. The Pacific–Siberian sector of the Arctic accounted for most of the summer sea-ice decline, while the winter recovery of sea ice in the Atlantic sector tended to decrease.

  16. Deglacial floods in the Beaufort Sea

    Science.gov (United States)

    Keigwin, L. D.; Driscoll, N. W.

    2014-12-01

    During summer 2013 USCGC Healy cruise 1302 surveyed and cored between Barrow, AK and the mouth of Amundsen Gulf, far to the east in the Beaufort Sea. Holocene deposition rates on the continental slope are high in the eastern Chukchi Sea and are lower farther east where deglacial sediments dominate. This is evident in CHIRP seismic data that trace two groups of reflectors as the sub-bottom depth between them increases. On the slope, at ~700 m w.d. near the mouth of the Mackenzie River, a pair of piston cores make a composite sequence 17 m long. The lower 4 m are sandy and capped by a maximum in magnetic susceptibility (ms) and a prominent reflector. N. pachyderma is too rare in this interval for 14C dates, but the d18-O of this species is as low as late Holocene. Above the reflector, counts of IRD are low, d18-O continues low, and the sediment is an acoustically transparent 7 m thick unit. The deepest date is 12.8 conv. 14C kyr at 13 m, and 3 overlying dates indicate the transparent unit accumulated at 8 m/14C kyr. The top of this unit is marked by the upper reflector that is in detail a triplet that corresponds to triple peaks in ms, grainsize, and IRD abundance. Between the two oldest sub-peaks of this reflector, d18-O reaches minimum values of ~1‰, or about 0.5‰ lower than late Holocene. In contrast to the deeper interval, this event is only 0.5 m thick and is dated to 11,050 conv. 14C kyr. Following this event, d18-O increases abruptly and then gradually decreases within the Holocene, more like a typical isotope stratigraphy. Overall, 9 dates indicate a gradual down-core increase in sedimentation rates from 9 cm/kyr in the late Holocene to the extreme of the deeper transparent unit with no age reversals. Using the modern Beaufort Sea Delta R (DR; 436 yrs), our oldest date calibrates to 13.8 ka, a little too old to be the cause of the Younger Dryas. However, the combined seismic, isotope, and sedimentological data suggest that at least the older transparent

  17. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  18. The thermodynamic state of the Arctic atmosphere observed by AIRS: comparisons during the record minimum sea-ice extents of 2007 and 2012

    Directory of Open Access Journals (Sweden)

    A. Devasthale

    2013-01-01

    Full Text Available The record sea-ice minimum (SIM extents observed during the summers of 2007 and 2012 in the Arctic are stark evidence of accelerated sea ice loss during the last decade. Improving our understanding of the Arctic atmosphere and accurate quantification of its characteristics becomes ever more crucial, not least to improve predictions of such extreme events in the future. In this context, the Atmospheric Infrared Sounder (AIRS instrument onboard NASA's Aqua satellite provides crucial insights due to its ability to provide 3-D information on atmospheric thermodynamics.

    Here, we facilitate comparisons in the evolution of the thermodynamic state of the Arctic atmosphere during these two SIM events using a decade long AIRS observational record (2003–2012. It is shown that the meteorological conditions during 2012 were not extreme but three factors in preconditioning from winter through early summer probably played an important role in accelerating sea-ice melt. First, the marginal sea-ice zones along the central Eurasian and North Atlantic sectors remained warm throughout winter and early spring in 2012 preventing thicker ice build-up. Second, the circulation pattern favoured efficient sea-ice transport out of the Arctic in the Atlantic sector during late spring and early summer in 2012 compared to 2007. Third, additional warming over the Canadian Archipelago and southeast Beaufort Sea from May onward further contributed to accelerated sea-ice melt. All these factors may have lead already thin and declining sea-ice cover to pass below the previous sea-ice extent minimum of 2007. In sharp contrast to 2007, negative surface temperature anomalies and increased cloudiness were observed over the East Siberian and Chukchi Seas in the summer of 2012. The results suggest that satellite-based monitoring of atmospheric preconditioning could be a critical source of information in predicting extreme sea-ice melting events in the Arctic.

  19. The thermodynamic state of the Arctic atmosphere observed by AIRS: comparisons during the record minimum sea ice extents of 2007 and 2012

    Directory of Open Access Journals (Sweden)

    A. Devasthale

    2013-08-01

    Full Text Available The record sea ice minimum (SIM extents observed during the summers of 2007 and 2012 in the Arctic are stark evidence of accelerated sea ice loss during the last decade. Improving our understanding of the Arctic atmosphere and accurate quantification of its characteristics becomes ever more crucial, not least to improve predictions of such extreme events in the future. In this context, the Atmospheric Infrared Sounder (AIRS instrument onboard NASA's Aqua satellite provides crucial insights due to its ability to provide 3-D information on atmospheric thermodynamics. Here, we facilitate comparisons in the evolution of the thermodynamic state of the Arctic atmosphere during these two SIM events using a decade-long AIRS observational record (2003–2012. It is shown that the meteorological conditions during 2012 were not extreme, but three factors of preconditioning from winter through early summer played an important role in accelerating sea ice melt. First, the marginal sea ice zones along the central Eurasian and North Atlantic sectors remained warm throughout winter and early spring in 2012 preventing thicker ice build-up. Second, the circulation pattern favoured efficient sea ice transport out of the Arctic in the Atlantic sector during late spring and early summer in 2012 compared to 2007. Third, additional warming over the Canadian archipelago and southeast Beaufort Sea from May onward further contributed to accelerated sea ice melt. All these factors may have lead the already thin and declining sea ice cover to pass below the previous sea ice extent minimum of 2007. In sharp contrast to 2007, negative surface temperature anomalies and increased cloudiness were observed over the East Siberian and Chukchi seas in the summer of 2012. The results suggest that satellite-based monitoring of atmospheric preconditioning could be a critical source of information in predicting extreme sea ice melting events in the Arctic.

  20. Variability and changes of Arctic sea ice draft distribution – submarine sonar measurements revisited

    Directory of Open Access Journals (Sweden)

    J. Haapala

    2011-10-01

    Full Text Available Changes in the mean sea ice thickness and concentration in the Arctic are well known. However, quantitative information about changes in the ice thickness distribution and the composition of the pack ice is lacking. In this paper we determine the ice draft distributions, mean and modal thicknesses, and their regional and seasonal variability in the Arctic for the time period 1975–2000. We compare characteristics of the Arctic pack ice for the years 1975–1987 and 1988–2000. These periods represent different large-scale atmospheric circulation modes and sea ice circulation patterns, most evident in clearly weaker Beaufort Gyre and stronger as well as westward shifted Transpolar Drift during the later period. The comparison of these two periods reveals that the peak of sea ice draft distributions has narrowed and shifted toward thinner ice, with reductions in both mean and modal ice draft. These noticeable changes are attributed to the loss of thick, mostly deformed ice. Springtime, loss of ice volume with draft greater than 5 m exceeds 35 % in all regions except the Nansen Basin, with as much as 45 % or more at the North Pole and in the Eastern Arctic. Autumn volume reduction, mostly of deformed ice, exceeds 40 % in the Canada Basin only, but is above 30 % also in the Beaufort and Chukchi Seas. During the later period, the volume of ice category consisting thin, mostly level first-year ice, is clearly larger than during the former period, especially in the spring. In the Beaufort Sea region, changes in the composition of ice cover have resulted in a shift of modal draft from level multiyear ice draft range to values of level first-year ice. The regional and seasonal variability of sea ice draft has decreased, since the thinning has been most pronounced in regions with the thickest pack ice (the Western Arctic, and during the spring (0.6–0.8 m per decade.

  1. Geostatistical and Statistical Classification of Sea-Ice Properties and Provinces from SAR Data

    Directory of Open Access Journals (Sweden)

    Ute C. Herzfeld

    2016-07-01

    Full Text Available Recent drastic reductions in the Arctic sea-ice cover have raised an interest in understanding the role of sea ice in the global system as well as pointed out a need to understand the physical processes that lead to such changes. Satellite remote-sensing data provide important information about remote ice areas, and Synthetic Aperture Radar (SAR data have the advantages of penetration of the omnipresent cloud cover and of high spatial resolution. A challenge addressed in this paper is how to extract information on sea-ice types and sea-ice processes from SAR data. We introduce, validate and apply geostatistical and statistical approaches to automated classification of sea ice from SAR data, to be used as individual tools for mapping sea-ice properties and provinces or in combination. A key concept of the geostatistical classification method is the analysis of spatial surface structures and their anisotropies, more generally, of spatial surface roughness, at variable, intermediate-sized scales. The geostatistical approach utilizes vario parameters extracted from directional vario functions, the parameters can be mapped or combined into feature vectors for classification. The method is flexible with respect to window sizes and parameter types and detects anisotropies. In two applications to RADARSAT and ERS-2 SAR data from the area near Point Barrow, Alaska, it is demonstrated that vario-parameter maps may be utilized to distinguish regions of different sea-ice characteristics in the Beaufort Sea, the Chukchi Sea and in Elson Lagoon. In a third and a fourth case study the analysis is taken further by utilizing multi-parameter feature vectors as inputs for unsupervised and supervised statistical classification. Field measurements and high-resolution aerial observations serve as basis for validation of the geostatistical-statistical classification methods. A combination of supervised classification and vario-parameter mapping yields best results

  2. Trophic cascades and future harmful algal blooms within ice-free Arctic Seas north of Bering Strait: A simulation analysis

    Science.gov (United States)

    Walsh, John J.; Dieterle, Dwight A.; Chen, F. Robert; Lenes, Jason M.; Maslowski, Wieslaw; Cassano, John J.; Whitledge, Terry E.; Stockwell, Dean; Flint, Mikhail; Sukhanova, Irina N.; Christensen, John

    2011-11-01

    Within larger ice-free regions of the western Arctic Seas, subject to ongoing trophic cascades induced by past overfishing, as well as to possible future eutrophication of the drainage basins of the Yukon and Mackenzie Rivers, prior very toxic harmful algal blooms (HABs) - first associated with ∼100 human deaths near Sitka, Alaska in 1799 - may soon expand. Blooms of calcareous coccolithophores in the Bering Sea during 1997-1998 were non-toxic harbingers of the subsequent increments of other non-siliceous phytoplankton. But, now saxitoxic dinoflagellates, e.g. Alexandrium tamarense, were instead found by us within the adjacent downstream Chukchi Sea during SBI cruises of 2002 and 2003. A previous complex, coupled biophysical model had been validated earlier by ship-board observations from the Chukchi/Beaufort Seas during the summer of 2002. With inclusion of phosphorus as another chemical state variable to modulate additional competition by recently observed nitrogen-fixers, we now explore here the possible consequences of altered composition of dominant phytoplankton functional groups [diatoms, microflagellates, prymnesiophyte Phaeocystis colonies, coccolithophores, diazotrophs, and dinoflagellates] in relation to increases of the toxic A. tamarense, responding to relaxation of grazing pressure by herbivores north of Bering Strait as part of a continuing trophic cascade. Model formulation was guided by validation observations obtained during 2002-2004 from: cruises of the SBI, CHINARE, and CASES programs; moored arrays in Bering Strait; other RUSALCA cruises around Wrangel Island; and SBI helicopter surveys of the shelf-break regions of the Arctic basin. Our year-long model scenarios during 2002-2003 indicate that post bloom silica-limitation of diatoms, after smaller simulated spring grazing losses, led to subsequent competitive advantages in summer for the coccolithophores, dinoflagellates, and diazotrophs. Immediate top-down control is exerted by imposed

  3. Multiyear ice transport and small scale sea ice deformation near the Alaska coast measured by air-deployable Ice Trackers

    Science.gov (United States)

    Mahoney, A. R.; Kasper, J.; Winsor, P.

    2015-12-01

    Highly complex patterns of ice motion and deformation were captured by fifteen satellite-telemetered GPS buoys (known as Ice Trackers) deployed near Barrow, Alaska, in spring 2015. Two pentagonal clusters of buoys were deployed on pack ice by helicopter in the Beaufort Sea between 20 and 80 km offshore. During deployment, ice motion in the study region was effectively zero, but two days later the buoys captured a rapid transport event in which multiyear ice from the Beaufort Sea was flushed into the Chukchi Sea. During this event, westward ice motion began in the Chukchi Sea and propagated eastward. This created new openings in the ice and led to rapid elongation of the clusters as the westernmost buoys accelerated away from their neighbors to the east. The buoys tracked ice velocities of over 1.5 ms-1, with fastest motion occurring closest to the coast indicating strong current shear. Three days later, ice motion reversed and the two clusters became intermingled, rendering divergence calculations based on the area enclosed by clusters invalid. The data show no detectable difference in velocity between first year and multiyear ice floes, but Lagrangian timeseries of SAR imagery centered on each buoy show that first year ice underwent significant small-scale deformation during the event. The five remaining buoys were deployed by local residents on prominent ridges embedded in the landfast ice within 16 km of Barrow in order to track the fate of such features after they detached from the coast. Break-up of the landfast ice took place over a period of several days and, although the buoys each initially followed a similar eastward trajectory around Point Barrow into the Beaufort Sea, they rapidly dispersed over an area more than 50 km across. With rapid environmental and socio-economic change in the Arctic, understanding the complexity of nearshore ice motion is increasingly important for predict future changes in the ice and the tracking ice-related hazards

  4. Holocene Northern Hemisphere sea-ice distribution - proxy data reconstruction and modelling

    Science.gov (United States)

    Seidenkrantz, Marit-Solveig; de Vernal, Anne; Goosse, Hugues; Klein, François; Solignac, Sandrine; Van Nieuwenhove, Nicolas; Pearce, Christof; Caissie, Beth; Belt, Simon; Sha, Longbin; Cronin, Thomas M.; Stein, Rüdiger; Macias-Fauria, Marc; DeNinno, Lauren H.

    2016-04-01

    A strikingly fast decrease of Arctic sea-ice cover has been recorded for the instrumental period and attributed to anthropogenic climate change, but little is known about natural sea-ice variability. Hence, there is a need for longer sea-ice time series to establish a baseline for natural Arctic sea-ice variability. We compiled 120 proxy-based sea-ice reconstructions from the Arctic Ocean and subarctic marginal seas to evaluate the stability/variability of sea-ice cover during the Holocene. The reconstructions are primarily based on published data combined with a few yet-unpublished records of biological (diatoms, dinoflagellate cysts, foraminifera, ostracods), sedimentological (IRD), and biogeochemical (IP25, PIP25, TOC) sea-ice indicators. Each indicator and record has been interpreted independently. We present all data as long-term annual means (months of sea ice per year). Sea-ice reconstructions are grouped into these classes: perennial (11-12 month/yr), dense (6-10 m/yr), common (1-6 m/yr), occasional (0.1-1 m/yr), rare (almost never) and absent (never). Further, reconstructions are made for the time slices 0-2 cal. ka (BP), 2-4 ka, 4-6 ka, 6±0.5 ka, 6-8 ka and 8-10 ka. Our study shows that winter sea ice was present during the entire Holocene, but summer sea ice may have been somewhat reduced in some areas during the Holocene Climate Optimum (10-6 ka), with variations between basins. In the Nordic Seas and N Atlantic minimum sea-ice conditions are seen 10-6 ka, whereas in the eastern Labrador Sea minimum sea-ice occurred 6-4 ka. Since ~4 ka sea-ice cover has increased, especially in the most recent millennia. Changes are subtle, however, but nonetheless consistent. The Pacific sector of the Arctic (Bering, Chukchi, Beaufort, Laptev, Okhotsk seas) shows less variability during the Holocene, though it is noted that these records have poorer age control and resolution than those from the Atlantic sector. It is noteworthy that, within the available temporal

  5. Providing Real-time Sea Ice Modeling Support to the U.S. Coast Guard

    Science.gov (United States)

    Allard, Richard; Dykes, James; Hebert, David; Posey, Pamela; Rogers, Erick; Wallcraft, Alan; Phelps, Michael; Smedstad, Ole Martin; Wang, Shouping; Geiszler, Dan

    2016-04-01

    The Naval Research Laboratory (NRL) supported the U.S. Coast Guard Research Development Center (RDC) through a demonstration project during the summer and autumn of 2015. Specifically, a modeling system composed of a mesoscale atmospheric model, regional sea ice model, and regional wave model were loosely coupled to provide real-time 72-hr forecasts of environmental conditions for the Beaufort/Chukchi Seas. The system components included a 2-km regional Community Ice CodE (CICE) sea ice model, 15-km Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS) atmospheric model, and a 5-km regional WAVEWATCH III wave model. The wave model utilized modeled sea ice concentration fields to incorporate the effects of sea ice on waves. The other modeling components assimilated atmosphere, ocean, and ice observations available from satellite and in situ sources. The modeling system generated daily 72-hr forecasts of synoptic weather (including visibility), ice drift, ice thickness, ice concentration and ice strength for missions within the economic exclusion zone off the coast of Alaska and a transit to the North Pole in support of the National Science Foundation GEOTRACES cruise. Model forecasts graphics were shared on a common web page with selected graphical products made available via ftp for bandwidth limited users. Model ice thickness and ice drift show very good agreement compared with Cold Regions Research and Engineering Laboratory (CRREL) Ice Mass Balance buoys. This demonstration served as a precursor to a fully coupled atmosphere-ocean-wave-ice modeling system under development. National Ice Center (NIC) analysts used these model data products (CICE and COAMPS) along with other existing model and satellite data to produce the predicted 48-hr position of the ice edge. The NIC served as a liaison with the RDC and NRL to provide feedback on the model predictions. This evaluation provides a baseline analysis of the current models for future comparison studies

  6. Mammals of the Sea.

    Science.gov (United States)

    Naturescope, 1986

    1986-01-01

    Presents information on sea mammals, including definitions and characteristics of cetaceans, pinnipeds, and sirenians. Contains descriptions of the teaching activities "Whale Music,""Draw A Whale to Scale,""Adopt a Sea Mammal," and "Sea Mammal Sleuths." (TW)

  7. Synoptic measurements of subsurface phytoplankton layers collected from Fish Lidar, Oceanic, Experimenta (FLOE) Light Detection and Ranging (LIDAR) from aircraft in Chukchi Sea and Beaufort Sea from 2014-07-17 to 2014-07-29 (NCEI Accession 0128217)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In July 2014, FLOE was installed in a NOAA Twin Otter to make the first synoptic measurements of subsurface phytoplankton layers associated with the retreating ice...

  8. 北极楚科奇海海冰面积多年变化的研究%Study on the multi-year variations of sea ice cover of Chukchi Sea in Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    朱大勇; 赵进平; 史久新

    2007-01-01

    北极气候系统正在发生显著变化,其中,海冰面积和厚度的减小是其最主要的特征.楚科奇海是海冰面积变化最有代表性的区域.文章利用积累了9 a的高分辨率海冰分布数据研究海冰面积的多年变化特征.结果表明,各年的冰情有显著的季节内变化,海冰面积距平曲线体现了不同时期海冰面积变化的动态过程.在1997~2005年间,楚科奇海海冰面积经历了轻(1997年)-重(2000~2001年)-轻(2002~2005年)的变化过程.9 a的数据总体上体现了海冰面积减小的趋势,2005年的冰情呈现了历史新低.每年融冰期的长短与冰情轻重有密切的关系,冰轻年份融冰开始时间早,冻结结束时间晚.各年海冰面积最小值发生在9月下旬至10月初,各个年份海冰最小面积差别很大.有的年份只有4%,而重冰年可以大于50%.文章采用4个重要参数表达海冰多年变化.其中海冰面积指数反映了当年总体平均的海冰面积距平;海冰最小面积反映了融冰期海冰的极限情况;上一个冬季的气温积温也与翌年海冰面积有良好的关联;分析了风场对海冰的影响,表明风场在融冰期能够在短时间内改变海冰的覆盖面积.

  9. Atmospheric Profiles, Clouds, and the Evolution of Sea Ice Cover in the Beaufort and Chukchi Seas: Atmospheric Observations and Modeling as Part of the Seasonal Ice Zone Reconnaissance Surveys

    Science.gov (United States)

    2015-09-30

    gliding unmanned aerial vehicle ( UAV ) that can also be dropped from a manned aircraft, but then can be guided to areas of interest (e.g. seasonal ice...APPLICATIONS The vertical structure of the atmospheric profiles and cloud are regulated by the synoptic conditions. Using our k-mean classification

  10. Aureimonas glaciistagni sp. nov., isolated from a melt pond on Arctic sea ice.

    Science.gov (United States)

    Cho, Yirang; Lee, Inae; Yang, Yoon Y; Baek, Kiwoon; Yoon, Soo J; Lee, Yung M; Kang, Sung-Ho; Lee, Hong K; Hwang, Chung Y

    2015-10-01

    A Gram-staining-negative, motile, aerobic and rod-shaped bacterial strain, PAMC 27157T, was isolated from a melt pond on sea ice in the Chukchi Sea. Phylogenetic analysis of the 16S rRNA gene sequence of strain PAMC 27157T revealed an affiliation to the genus Aureimonas with the closest sequence similarity (96.2 %) to that of Aureimonas phyllosphaerae. Strain PAMC 27157T grew optimally at 30 °C and pH 7.0 in the presence of 3.5 % (w/v) NaCl. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, sulfoquinovosyldiacylglycerol and an unidentified aminolipid. The major cellular fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c, 83.1 %) and the major respiratory quinone was Q-10. The genomic DNA G+C content was 69.1 mol%. The combined phylogenetic, phenotypic and chemotaxonomic data showed that strain PAMC 27157T could be clearly distinguished from species of the genus Aureimonas with validly published names. Thus, strain PAMC 27157T should be classified as representing a novel species in the genus Aureimonas, for which the name Aureimonas glaciistagni sp. nov. is proposed. The type strain is PAMC 27157T ( = KCCM 43049T = JCM 30183T).

  11. Historical temperature, salinity, oxygen, pH, and meteorological data collected from Former Soviet Union platforms Lomonosov, Murmanets, and Akademik Shokalsky in 1933 - 1962 years from Arctic Ocean, Barents Sea, Bering Sea, Chukchi Sea, East Siberian Sea, Kara Sea, and Laptev Sea (NODC Accession 0108117)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Historical temperature, salinity, oxygen, pH, and meteorological data collected from Former Soviet Union platforms Lomonosov,Murmanets, and Akademik Shokalsky in...

  12. Productivity, chlorophyll a, Photosynthetically Active Radiation (PAR) and other phytoplankton data from the Arctic Ocean, Bering Sea, Chukchi Sea, Beaufort Sea, East Siberian Sea, Kara Sea, Barents Sea, and Arctic Archipelago measured between 17 April, 1954 and 30 May, 2006 compiled as part of the Arctic System Science Primary Production (ARCSS-PP) observational synthesis project (NODC Accession 0063065)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Arctic Ocean primary production data were assembled from original input data archived in various international databases, provided by individual investigators or in...

  13. Pollen evidence for late pleistocene bering land bridge environments from Norton Sound, Northeastern Bering Sea, Alaska

    Science.gov (United States)

    Ager, T.A.; Phillips, R.L.

    2008-01-01

    After more than half a century of paleoenvironmental investigations, disagreements persist as to the nature of vegetation type and climate of the Bering land bridge (BLB) during the late Wisconsin (Sartan) glacial interval. Few data exist from sites on the former land bridge, now submerged under the Bering and Chukchi Seas. Two hypotheses have emerged during the past decade. The first, based on pollen data from Bering Sea islands and adjacent mainlands of western Alaska and Northeast Siberia, represents the likely predominant vegetation on the Bering land bridge during full-glacial conditions: graminoid-herb-willow tundra vegetation associated with cold, dry winters and cool, dry summer climate. The second hypothesis suggests that dwarf birch-shrub-herb tundra formed a broad belt across the BLB, and that mesic vegetation was associated with cold, snowier winters and moist, cool summers. As a step towards resolving this controversy, a sediment core from Norton Sound, northeastern Bering Sea was radiocarbon dated and analyzed for pollen content. Two pollen zones were identified. The older, bracketed by radiocarbon ages of 29,500 and 11,515 14C yr BP, contains pollen assemblages composed of grass, sedge, wormwood, willow, and a variety of herb (forb) taxa. These assemblages are interpreted to represent graminoid-herb-willow tundra vegetation that developed under an arid, cool climate regime. The younger pollen zone sediments were deposited about 11,515 14C yr BP, when rising sea level had begun to flood the BLB. This younger pollen zone contains pollen of birch, willow, heaths, aquatic plants, and spores of sphagnum moss. This is interpreted to represent a Lateglacial dwarf birch-heath-willow-herb tundra vegetation, likely associated with a wetter climate with deeper winter snows, and moist, cool summers. This record supports the first hypothesis, that graminoid-herb-willow tundra vegetation extended into the lowlands of the BLB during full glacial conditions of the

  14. The Timing of Arctic Sea Ice Advance and Retreat as an Indicator of Ice-Dependent Marine Mammal Habitat

    Science.gov (United States)

    Stern, H. L.; Laidre, K. L.

    2013-12-01

    The Arctic is widely recognized as the front line of climate change. Arctic air temperature is rising at twice the global average rate, and the sea-ice cover is shrinking and thinning, with total disappearance of summer sea ice projected to occur in a matter of decades. Arctic marine mammals such as polar bears, seals, walruses, belugas, narwhals, and bowhead whales depend on the sea-ice cover as an integral part of their existence. While the downward trend in sea-ice extent in a given month is an often-used metric for quantifying physical changes in the ice cover, it is not the most relevant measure for characterizing changes in the sea-ice habitat of marine mammals. Species that depend on sea ice are behaviorally tied to the annual retreat of sea ice in the spring and advance in the fall. Changes in the timing of the spring retreat and the fall advance are more relevant to Arctic marine species than changes in the areal sea-ice coverage in a particular month of the year. Many ecologically important regions of the Arctic are essentially ice-covered in winter and ice-free in summer, and will probably remain so for a long time into the future. But the dates of sea-ice retreat in spring and advance in fall are key indicators of climate change for ice-dependent marine mammals. We use daily sea-ice concentration data derived from satellite passive microwave sensors to calculate the dates of sea-ice retreat in spring and advance in fall in 12 regions of the Arctic for each year from 1979 through 2013. The regions include the peripheral seas around the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev, Kara, Barents), the Canadian Arctic Archipelago, and the marginal seas (Okhotsk, Bering, East Greenland, Baffin Bay, Hudson Bay). We find that in 11 of the 12 regions (all except the Bering Sea), sea ice is retreating earlier in spring and advancing later in fall. Rates of spring retreat range from -5 to -8 days/decade, and rates of fall advance range from +5 to +9

  15. White sea radioactivity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, R.A. [Lomonosov Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics]|[Lomonosov Moscow State Univ. (Russian Federation). Chemistry Dept.]|[Russian Academy of Sciences, Moscow (Russian Federation). Shirshov Inst. of Oceanology; Kalmykov, S.N.; Lisitzin, A.P. [Lomonosov Moscow State Univ. (Russian Federation). Chemistry Dept.

    2004-07-01

    The aim of the present work is to estimate potential sources and chronology of pollution of the White Sea (Russia) by artificial radionuclides. White Sea is semi-closed water body connected with Barents Sea by a narrow strait. Thus, pollution of White Sea may be caused by highly polluted Barents waters and river (mainly Northern Dvina) run-off. This is the first detailed investigation of radioactivity of White Sea sediment records. (orig.)

  16. LATE QUATERNARY TERRIGENOUS DEPOSITS FROM CORE P31 ON THE CHUKCHI PLATEAU OF WESTERN ARCTIC OCEAN AND THEIR PALEOCEANOGRAPHIC AND PALEOCLIMATIC IMPLICATIONS%西北冰洋楚科奇海台P31孔晚第四纪的陆源沉积物记录及其古海洋与古气候意义

    Institute of Scientific and Technical Information of China (English)

    梅静; 王汝建; 陈建芳; 程振波; 陈志华; 孙烨忱

    2012-01-01

    Stage (MIS) 3. A total of five IRD events were distinguished during the late MIS 1, MIS 2 and early to mid MIS 3. These IRD, transported by sea ice and icebergs, and brought to the Chukchi Plateau, by the Beaufort Gyre, might be exported from the M'Clure Strait Ice Stream, Canadian Arctic Archipelago. They are indicators of the collapse events of North American Ice Sheet (NAIS) and the evolutionary history of the Beaufort Gyre since MIS 3. Grain size components changes show that the sand components, which correspond to the high IRD size fraction, might be transported by icebergs: but the silt components might be mainly transported by sea ice, and the clay component was probably mainly carried by the Beaufort Gyre. The variation of two sensitive components (5-13 μm and 110-176 μm) present clear symmetric distribution, the coarser component corresponds to the IRD, and the finer may indicate the source region and the influence of deposition. During MIS 3, MIS 2 and MIS 1, the sedimentation rates of core P31 are 2. 2 cm/ka, 0. 16 cm/ka and 1. 6 cm/ka, respectively. The average sedimentation rate is about 1. 2 cm/ka. The overall picture of the western Arctic Ocean shows high sedimentation rates in the ice edge, and low sedimentation rates in areas with permanent sea ice cover. High sedimentation rates occur in areas of shallow water depth, and close to the terrigenous source regions, and low sedimentation rates in the high latitude area of Mendeleev-alpha ridge and Canada Basin area.

  17. 1979—2012年北极海冰运动学特征初步分析%Preliminary analysis of kinematic characteristics of Arctic sea ice from 1979 to 2012

    Institute of Scientific and Technical Information of China (English)

    左正道; 高郭平; 程灵巧; 徐飞翔

    2016-01-01

    in 2007 and 2012,theeffects of surface wind and sea level pressure on Arctic sea ice motion were also investigated.The results showedthat the Arctic sea ice motion was accelerating with rate of 2.1%/a in winter and 1.7%/a in summer.In theBeaufort-Chukchi area and the Fram Strait area,the accelerating rates were 2.0%/a and 4.9%/a in winter,1.6%/a and 2.2%/a in summer,respectively.There was a significant negative correlation between sea ice motionand sea ice extent,with a correlation coefficient was —0.77 from 1979 to 2012.The tendency of wind field in winterand summer was in accord with that of mean sea ice motion with correlation coefficients of 0.50 and 0.48,respectively.The influence of sea surface wind and sea level pressure on sea ice motion,divergence and redistributionwas significant.From 234th to 273rd in summer of 2007,high pressure system controlled the Beaufort Sea,leadingto southerly wind in Bering Strait and Chukchi Sea.As well as,the stronger Beaufort Gyre made sea ice detainedin the central Arctic and the clockwise wind filed drove sea ice aggregate north of Greenland and CanadianArctic Archipelago.In 2012,both the Bering Strait and the Chukchi Sea were at the junction of the low and highpressure systems,northerly wind during the same period as 2007.Under the joint action of low pressure and highpressure systems,sea ice was transported from the east towards west in the Arctic Ocean.The multiyear sea ice inthe Canadian Basin was diverged driven by the offshore movement,and transported towards Chukchi Sea and increasedthe melting by the Pacific warm inflow.

  18. Alpha / Mendeleev Ridge and Chukchi Borderland 40Ar/39Ar Geochronology and Geochemistry: Character of the First Submarine Intraplate Lavas Recovered from the Arctic Ocean

    Science.gov (United States)

    Mukasa, Samuel B.; Mayer, Larry A.; Aviado, Kimberly; Bryce, Julie; Andronikov, Alex; Brumley, Kelley; Blichert-Toft, Janne; Petrov, Oleg; Shokalsky, Sergey

    2015-04-01

    At least three episodes of magmatic activity have been recognized on the basis of 40Ar/39Ar age determinations in the submarine basaltic samples dredged, drilled or grabbed with a manipulation arm from Alpha / Mendeleev Ridge and Chukchi Borderland of the Arctic Ocean by US Coast Guard Icebreaker Healy, in August-September 2008, and Russian research vessel Captain Dranitsin in August-October 2012: ca. 112 Ma, ca. 100 Ma and ca. 85-73 Ma. Major-oxide and trace-element concentrations, and Pb, Sr, Nd, and Hf isotopic ratios of the recovered lavas provide important constraints on the composition and sources for the original melts. Lavas erupted at ca. 112 Ma (Group 1) have alkali basalt major-oxide compositions. Their low degree of rare-earth-element (REE) fractionation (CeN/YbN = 1.7-2.5), combined with high overall HREE (22-24 times chondrite) and Mg# ~54, suggest derivation from a garnet-free source followed by only minimal crystal fractionation for this group. Pb-Sr-Nd-Hf isotopic systematics of the lavas (206Pb/204Pb = 18.73-18.79; 207Pb/204Pb = 15.54-15.56; 208Pb/204Pb = 38.28-38.35; 143Nd/144Nd = 0.512594-0.512610; 87Sr/86Sr = 0.709458-0.709601; 176Hf/177Hf = 0.283224), together with ratios of highly incompatible trace elements (Th/Ce = 0.09-0.11; Ce/Nb = 2.58-3.09; Th/Nb = 0.24-0.33), point toward a lithospheric source for the magmas. Eruptions at ca. 100 Ma and 85-73 Ma produced two types of lavas: low-Ti tholeiitic basalts - LT, and high-Ti alkali basalts - HT, both assigned to Group 2. This distribution of low- and high-Ti lavas is common in continental flood basalt (CFB) provinces elsewhere, and has been attributed to plume activity in some studies. The trace-element abundance patterns for these Group 2 Arctic lavas are also very similar to those of CFBs elsewhere. Their low degrees of REE fractionation (CeN/YbN = 2.0-3.3) accompanied by progressively decreasing Mg#s (from 53 to 33) suggest a garnet-free source, with the derivative magmas experiencing

  19. 7 CFR 1437.310 - Sea grass and sea oats.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value...

  20. Coastal Vulnerability to Sea Level Rise and Erosion in Northwest Alaska (Invited)

    Science.gov (United States)

    Gorokhovich, Y.; Leiserowitz, A.

    2009-12-01

    Northwest Alaska is experiencing significant climate change and human impacts. The study area includes the coastal zone of Kotzebue Sound and the Chukchi Sea and provides the local population (predominantly Inupiaq Eskimo) with critical subsistence resources of meat, fish, berries, herbs, and wood. The geomorphology of the coast includes barrier islands, inlets, estuaries, deltas, cliffs, bluffs, and beaches that host modern settlements and infrastructure. Coastal dynamics and sea-level rise are contributing to erosion, intermittent erosion/accretion patterns, landslides, slumps and coastal retreat. These factors are causing the sedimentation of deltas and lagoons, and changing local bathymetry, morphological parameters of beaches and underwater slopes, rates of coastal dynamics, and turbidity and nutrient cycling in coastal waters. This study is constructing vulnerability maps to help local people and federal officials understand the potential consequences of sea-level rise and coastal erosion on local infrastructure, subsistence resources, and culturally important sites. A lack of complete and uniform data (in terms of methods of collection, geographic scale and spatial resolution) creates an additional level of uncertainty that complicates geographic analysis. These difficulties were overcome by spatial modeling with selected spatial resolution using extrapolation methods. Data include subsistence resource maps obtained using Participatory GIS with local hunters and elders, geological and geographic data on coastal dynamics from satellite imagery, aerial photos, bathymetry and topographic maps, and digital elevation models. These data were classified and ranked according to the level of coastal vulnerability (Figure 1). The resulting qualitative multicriteria model helps to identify the coastal areas with the greatest vulnerability to coastal erosion and of the potential loss of subsistence resources. Acknowldgements: Dr. Ron Abileah (private consultant, j

  1. Development of statistical seasonal prediction models of Arctic Sea Ice concentration using CERES absorbed solar radiation

    Science.gov (United States)

    Kim, Yoojin; Kim, Ha-Rim; Choi, Yong-Sang; Kim, WonMoo; Kim, Hye-Sil

    2016-11-01

    Statistical seasonal prediction models for the Arctic sea ice concentration (SIC) were developed for the late summer (August-October) when the downward trend is dramatic. The absorbed solar radiation (ASR) at the top of the atmosphere in June has a significant seasonal leading role on the SIC. Based on the lagged ASR-SIC relationship, two simple statistical models were established: the Markovian stochastic and the linear regression models. Crossvalidated hindcasts of SIC from 1979 to 2014 by the two models were compared with each other and observation. The hindcasts showed general agreement between the models as they share a common predictor, ASR in June and the observed SIC was well reproduced, especially over the relatively thin-ice regions (of one- or multi-year sea ice). The robust predictability confirms the functional role of ASR in the prediction of SIC. In particular, the SIC prediction in October was quite promising probably due to the pronounced icealbedo feedback. The temporal correlation coefficients between the predicted SIC and the observed SIC were 0.79 and 0.82 by the Markovian and regression models, respectively. Small differences were observed between the two models; the regression model performed slightly better in August and September in terms of temporal correlation coefficients. Meanwhile, the prediction skills of the Markovian model in October were higher in the north of Chukchi, the East Siberian, and the Laptev Seas. A strong non-linear relationship between ASR in June and SIC in October in these areas would have increased the predictability of the Markovian model.

  2. Sea Lion Diet Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — California sea lions pup and breed at four of the nine Channel Islands in southern California. Since 1981, SWFSC MMTD has been conducting a diet study of sea lions...

  3. Sea Turtle Interaction Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Turtle Interaction Report is a report sent out in pdf format to authorized individuals that summarizes sea turtle interactions in the longline fishery. The...

  4. On measurements of aerosol-gas composition of the atmosphere during two expeditions in 2013 along the Northern Sea Route

    Science.gov (United States)

    Sakerin, S. M.; Bobrikov, A. A.; Bukin, O. A.; Golobokova, L. P.; Pol'kin, Vas. V.; Pol'kin, Vik. V.; Shmirko, K. A.; Kabanov, D. M.; Khodzher, T. V.; Onischuk, N. A.; Pavlov, A. N.; Potemkin, V. L.; Radionov, V. F.

    2015-11-01

    We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric aerosol in areas of the Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August-22 September 2013) and RV Professor Khljustin (24 July-7 September 2013). The specific features of spatial distribution and time variations of aerosol optical depth (AOD) of the atmosphere in the wavelength range of 0.34-2.14 μm and boundary layer height, aerosol and black carbon mass concentrations, and disperse and chemical composition of aerosol are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in aerosol and black carbon concentrations in a northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm) values in this remote region were 0.03; the aerosol and black carbon mass concentrations were 875 and 22 ng m-3, respectively. The spatial distributions of most aerosol characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from the Japan Sea to the Chukchi Sea, the aerosol number concentration decreased on average from 23.7 to 2.5 cm-3, the black carbon mass concentration decreased from 150 to 50 ng m-3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary layer height, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary layer height, there is a characteristic minimum at a latitude of ~ 55° N. For water basins of eight seas, we present the chemical compositions of the water-soluble aerosol fraction (ions, elements) and small gas-phase species, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75-89 %) supplied from the atmosphere to the sea

  5. In-situ measured primary productivity of ice algae in Arctic sea ice floes using a new incubation method

    Science.gov (United States)

    Song, Ho Jung; Lee, Jae Hyung; Kim, Gawn Woo; Ahn, So Hyun; Joo, Houng-Min; Jeong, Jin Young; Yang, Eun Jin; Kang, Sung-Ho; Lee, Sang Heon

    2016-09-01

    Recent changes in climate and environmental conditions have had great negative effects such as decreasing sea ice thickness and the extent of Arctic sea ice floes that support ice-related organisms. However, limited field observations hinder the understanding of the impacts of the current changes in the previously ice-covered regions on sea ice algae and other ice-related ecosystems. Our main objective in this study was to measure recent primary production of ice algae and their relative contribution to total primary production (ice plus pelagic primary production). In-situ primary productivity experiments with a new incubation system for ice algae were conducted in 3 sea ice cores at 2 different ice camps in the northern Chukchi Sea, 2014, using a 13C and 15N isotope tracer technique. A new incubation system was tested for conducting primary productivity experiments on ice algae that has several advantages over previous incubation methods, enabling stable carbon and nitrogen uptake experiments on ice algae under more natural environmental conditions. The vertical C-shaped distributions of the ice algal chl- a, with elevated concentrations at the top and bottom of the sea ice were observed in all cores, which is unusual for Arctic sea ice. The mean chl- a concentration (0.05 ± 0.03 mg chl- a m-3) and the daily carbon uptake rates (ranging from 0.55 to 2.23 mg C m-2 d-1) for the ice algae were much lower in this study than in previous studies in the Arctic Ocean. This is likely because of the late sampling periods and thus the substantial melting occurring. Ice algae contributed 1.5-5.7% of the total particulate organic carbon (POC) contents of the combined euphotic water columns and sea ice floes. In comparison, ice algae contributed 4.8-8.6% to the total primary production which is greater than previously reported in the Arctic Ocean. If all of the ice-associated productions were included, the contributions of the sea ice floes to the total primary production

  6. The Caspian Sea Environment

    Science.gov (United States)

    Kostianoy, Andrey; Kosarev, A.

    The systematic description of the knowledge accumulated on the physical oceanography, marine chemistry and pollution, and marine biology of the Caspian Sea forms the basis of this book. It presents the principal characteristic features of the environmental conditions of the sea and their changes in the second half of the 20th century. At present, the principal problems of the Caspian Sea are related to the interannual sea level changes and their forecast and to the estimation of the intensity of the chemical pollution of the sea and its impact upon the biota.

  7. SEA and planning

    DEFF Research Database (Denmark)

    Stoeglehner, G.; Brown, A.L.; Kørnøv, Lone

    2009-01-01

    As the field of strategic environmental assessment (SEA) has matured, the focus has moved from the development of legislation, guidelines and methodologies towards improving the effectiveness of SEA. Measuring and of course achieving effectiveness is both complex and challenging. This paper...... suggests that SEA professionals need to consider 'democratic effectiveness' as well as 'environmental effectiveness' in both 'direct' and 'indirect' outputs. The effectiveness of SEA depends critically on the context within which SEA legislation and guidelines are understood and implemented......, and the relationship of the SEA to the planning activity itself. This paper focuses on the influence that planners have in these implementation processes, postulating the hypothesis that these are key players in achieving effectiveness in SEA. Based upon implementation theory and empirical experience, the paper...

  8. Sea piracy and law of the sea

    OpenAIRE

    Hanif, Muhammad Tahir

    2010-01-01

    As the sea become world’s largest source to trade between the nations during the last few decades. Of course there are lots of problems in this regards when we are using the sea on such a large scale. The problem of piracy is most dangerous problems, among the all problems of the sea at the same time. Nations are trying to control this crime individually and collectively but the problem is still on its peak. Lots of international and national laws and conventions are held in this ...

  9. Salish Sea Genetics - Salish Sea genetic inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Salish Sea comprises most of the Puget Sound water area. Marine species are generally assemblages of discrete populations occupying various ecological niches....

  10. Summer Arctic sea fog

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Synchronous or quasi-synchronous sea-land-air observations were conducted using advanced sea ice, atmospheric and marine instruments during China' s First Arctic Expedition. Based on the Precious data from the expedition, it was found that in the Arctic Ocean, most part of which is covered with ice or is mixed with ice, various kinds of sea fog formed such as advection fog, radiation fog and vapor fog. Each kind has its own characteristic and mechanics of creation. In the southern part of the Arctic Ocean, due to the sufficient warm and wet flow there, it is favorable for advection fog to form,which is dense and lasts a long time. On ice cap or vast floating ice, due to the strong radiation cooling effect, stable radiating fog is likely to form. In floating ice area there forms vapor fog with the appearance of masses of vapor from a boiling pot, which is different from short-lasting land fog. The study indicates that the reason why there are many kinds of sea fog form in the Arctic Ocean is because of the complicated cushion and the consequent sea-air interaction caused by the sea ice distribution and its unique physical characteristics. Sea fog is the atmospheric phenomenon of sea-air heat exchange. Especially, due to the high albedo of ice and snow surface, it is diffcult to absorb great amount of solar radiation during the polar days. Besides, ice is a poor conductor of heat; it blocks the sea-air heat exchange.The sea-air exchange is active in floating ice area where the ice is broken. The sea sends heat to the atmosphere in form of latent heat; vapor fog is a way of sea-air heat exchange influencing the climate and an indicator of the extent of the exchange. The study also indicates that the sea also transports heat to the atmosphere in form of sensible heat when vapor fog occurs.

  11. On measurements of aerosol-gas composition of the atmosphere during two expeditions in 2013 along Northern Sea Route

    Science.gov (United States)

    Sakerin, S. M.; Bobrikov, A. A.; Bukin, O. A.; Golobokova, L. P.; Pol'kin, Vas. V.; Pol'kin, Vik. V.; Shmirko, K. A.; Kabanov, D. M.; Khodzher, T. V.; Pavlov, A. N.; Potemkin, V. L.; Radionov, V. F.

    2015-06-01

    We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric aerosol in water basins of Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August-22 September 2013) and RV Professor Khljustin (24 July-7 September 2013). The specific features of spatial distribution and time variations of aerosol optical depth (AOD) of the atmosphere in the wavelength range of 0.34-2.14 μm and boundary layer height, aerosol and black carbon mass concentrations, and disperse and chemical composition of aerosol are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in aerosol and black carbon concentrations in northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm) values in this remote region were 0.03; the aerosol and black carbon mass concentrations were 875 and 22 ng m-3, respectively. The spatial distributions of most aerosol characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from Japan to Chukchi Sea, the aerosol number concentration decreased, on the average, from 23.7 to 2.5 cm-3, the black carbon mass concentration decreased from 150 to 50 ng m-3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary layer height, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary layer height, there is a characteristic minimum at latitude of ∼ 55° N. For water basins of eight seas, we present the chemical compositions of water-soluble aerosol fraction (ions, elements) and small gaseous impurities, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75-89 %) supplied from the atmosphere to the sea surface

  12. On measurements of aerosol–gas composition of the atmosphere during two expeditions in 2013 along Northern Sea Route

    Directory of Open Access Journals (Sweden)

    S. M. Sakerin

    2015-06-01

    Full Text Available We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric aerosol in water basins of Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August–22 September 2013 and RV Professor Khljustin (24 July–7 September 2013. The specific features of spatial distribution and time variations of aerosol optical depth (AOD of the atmosphere in the wavelength range of 0.34–2.14 μm and boundary layer height, aerosol and black carbon mass concentrations, and disperse and chemical composition of aerosol are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov there is a decrease in aerosol and black carbon concentrations in northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm values in this remote region were 0.03; the aerosol and black carbon mass concentrations were 875 and 22 ng m-3, respectively. The spatial distributions of most aerosol characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from Japan to Chukchi Sea, the aerosol number concentration decreased, on the average, from 23.7 to 2.5 cm-3, the black carbon mass concentration decreased from 150 to 50 ng m-3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary layer height, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary layer height, there is a characteristic minimum at latitude of ∼ 55° N. For water basins of eight seas, we present the chemical compositions of water-soluble aerosol fraction (ions, elements and small gaseous impurities, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75–89 % supplied from the atmosphere to

  13. Impact of Arctic sea-ice retreat on the recent change in cloud-base height during autumn

    Science.gov (United States)

    Sato, K.; Inoue, J.; Kodama, Y.; Overland, J. E.

    2012-12-01

    Cloud-base observations over the ice-free Chukchi and Beaufort Seas in autumn were conducted using a shipboard ceilometer and radiosondes during the 1999-2010 cruises of the Japanese R/V Mirai. To understand the recent change in cloud base height over the Arctic Ocean, these cloud-base height data were compared with the observation data under ice-covered situation during SHEBA (the Surface Heat Budget of the Arctic Ocean project in 1998). Our ice-free results showed a 30 % decrease (increase) in the frequency of low clouds with a ceiling below (above) 500 m. Temperature profiles revealed that the boundary layer was well developed over the ice-free ocean in the 2000s, whereas a stable layer dominated during the ice-covered period in 1998. The change in surface boundary conditions likely resulted in the difference in cloud-base height, although it had little impact on air temperatures in the mid- and upper troposphere. Data from the 2010 R/V Mirai cruise were investigated in detail in terms of air-sea temperature difference. This suggests that stratus cloud over the sea ice has been replaced as stratocumulus clouds with low cloud fraction due to the decrease in static stability induced by the sea-ice retreat. The relationship between cloud-base height and air-sea temperature difference (SST-Ts) was analyzed in detail using special section data during 2010 cruise data. Stratus clouds near the sea surface were predominant under a warm advection situation, whereas stratocumulus clouds with a cloud-free layer were significant under a cold advection situation. The threshold temperature difference between sea surface and air temperatures for distinguishing the dominant cloud types was 3 K. Anomalous upward turbulent heat fluxes associated with the sea-ice retreat have likely contributed to warming of the lower troposphere. Frequency distribution of the cloud-base height (km) detected by a ceilometer/lidar (black bars) and radiosondes (gray bars), and profiles of potential

  14. South China Sea Challenge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    China's attempts to solve disputes with ASEAN over the South China Sea help regional peace China's marine economy and security are currently faced with new challenges, requiring careful handling, especially in disputes with ASEAN countries and in promoting common development of the South China Sea. The outcome of how this is dealt with could undoubtedly pave the way for solutions to other oceanic disputes. The South China Sea is located south of

  15. Dilemmas in SEA application

    DEFF Research Database (Denmark)

    Lyhne, Ivar

    Dilemmas in SEA Application: The DK Energy SectorIvar Lyhne - lyhne@plan.aau.dk. Based on three years of collaborative research, this paper outlines dilemmas in the application of SEA in the strategic development of the Danish energy sector. The dilemmas are based on concrete examples from practice...... the Danish energy sector) are starting to get it right. Lessons for SEA implementation in similar contexts are proposed....

  16. Igneous rocks of Arctic Ocean deep sea ridges: new data on petrology, geochemistry and geochronology

    Science.gov (United States)

    Petrov, Oleg; Morozov, Andrey; Shokalsky, Sergey; Sobolev, Nikolay; Kashubin, Sergey; Shevchenko, Sergey; Sergeev, Sergey; Belyatsky, Boris; Shatov, Vitaly; Petrov, Eugeny

    2015-04-01

    The aggregate results of studies of igneous rocks, collected from the central part of the Arctic Ocean during scientific marine expeditions «Arctic-2000, 2005, 2007 and 2012» are presented and discussed in the frame of modern understanding of High Polar Arctic tectonic constraint. Petrological, geochemical and isotope-geochronological studies of more than 500 samples have shown that the sedimentary rocks are of dominated population among the rock fragments dredged from deep-sea bottom, and represented by metamorphosed dolomite and quartz sandstone, limestone, sometimes with the Devonian - Permian fauna. Igneous rocks are 10-15% only (Archean and Paleoproterozoic gneissouse granites and gabbro, Neoproterozoic dolerite) and metamorphic rocks (green shales, metabasites, gneisses). Apparently, these rocks are part of the acoustic basement underlying the Late Mesozoic - Cenozoic layered loose sediments. In addition to the dredged fragments of the ancient mafic rocks, some samples were taken as a core during deep-water drilling in the northern and southern slopes of the Mendeleev Ridge and represented by trachybasalts, marking the border of Late-Cenozoic deposit cover and acoustic basement and quite similar in composition to those of Early-Late Cretaceous basalts form northward of the Chukchi Plateau seamounts, Alpha Ridge, Franz Josef Land, De Long islands and other parts of the large igneous province of the High Arctic (HALIP). Video-filming of Mendeleev Ridge escarps proofs the existing of rock outcrops and supports local origin of most of the rock fragments found in the sampling areas. Thus the continental type of the earth's crust of the Central Arctic Ridges basement is based on all obtained results of our study of sea-bottom excavated rock material.

  17. Pelagic sea snakes dehydrate at sea

    Science.gov (United States)

    Lillywhite, Harvey B.; Sheehy, Coleman M.; Brischoux, François; Grech, Alana

    2014-01-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

  18. Sea surface temperatures and salinities from platforms in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and the South China Sea (Nan Hai) from 1896-1950 (NODC Accession 0000506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface temperatures and salinities were collected in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and South China Sea (Nan Hai)...

  19. Critical mechanisms for the formation of extreme arctic sea-ice extent in the summers of 2007 and 1996

    Science.gov (United States)

    Dong, Xiquan; Zib, Behnjamin J.; Xi, Baike; Stanfield, Ryan; Deng, Yi; Zhang, Xiangdong; Lin, Bing; Long, Charles N.

    2014-07-01

    Along with significant changes in the Arctic climate system, the largest year-to-year variation in sea-ice extent (SIE) has occurred in the Laptev, East Siberian, and Chukchi seas (defined here as the area of focus, AOF), among which the two highly contrasting extreme events were observed in the summers of 2007 and 1996 during the period 1979-2012. Although most efforts have been devoted to understanding the 2007 low, a contrasting high September SIE in 1996 might share some related but opposing forcing mechanisms. In this study, we investigate the mechanisms for the formation of these two extremes and quantitatively estimate the cloud-radiation-water vapor feedback to the sea-ice-concentration (SIC) variation utilizing satellite-observed sea-ice products and the NASA MERRA reanalysis. The low SIE in 2007 was associated with a persistent anticyclone over the Beaufort Sea coupled with low pressure over Eurasia, which induced anomalous southerly winds. Ample warm and moist air from the North Pacific was transported to the AOF and resulted in positive anomalies of cloud fraction (CF), precipitable water vapor (PWV), surface LWnet (down-up), total surface energy and temperature. In contrast, the high SIE event in 1996 was associated with a persistent low pressure over the central Arctic coupled with high pressure along the Eastern Arctic coasts, which generated anomalous northerly winds and resulted in negative anomalies of above mentioned atmospheric parameters. In addition to their immediate impacts on sea ice reduction, CF, PWV and radiation can interplay to lead to a positive feedback loop among them, which plays a critical role in reinforcing sea ice to a great low value in 2007. During the summer of 2007, the minimum SIC is 31 % below the climatic mean, while the maximum CF, LWnet and PWV can be up to 15 %, 20 Wm-2, and 4 kg m-3 above. The high anti-correlations (-0.79, -0.61, -0.61) between the SIC and CF, PWV, and LWnet indicate that CF, PWV and LW radiation

  20. Oceanography of marginal seas

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    in the marginal seas is low since the inflowing surface waters from the Arabian Sea are oligotrophic. High evaporative conditions in the Persian Gulf facilitate a carbonate precipitation of 125 mu mole kg-1 near the Trucial coast. The partial pressure of carbon...

  1. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki;

    2011-01-01

    . Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of 137Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout...

  2. IOMASA SEA ICE DEVELOPMENTS

    DEFF Research Database (Denmark)

    Andersen, Søren; Tonboe, Rasmus; Heygster, Georg

    2005-01-01

    Sensitivity studies show that the radiometer ice concentration estimate can be biased by +10% by anomalous atmospheric emissivity and -20% by anomalous ice surface emissivity. The aim of the sea ice activities in EU 5th FP project IOMASA is to improve sea ice concentration estimates at higher...... spatial resolution. The project is in the process of facilitating an ice concentration observing system through validation and a better understanding of the microwave radiative transfer of the sea ice and overlying snow layers. By use of a novel modelling approach, it is possible to better detect...... and determine the circumstances that may lead to anomalous sea ice concentration retrieval as well as to assess and possibly minimize the sensitivities of the retrieval system. Through an active partnership with the SAF on Ocean and Sea Ice, a prototype system will be implemented as an experimental product...

  3. Indicators and SEA

    DEFF Research Database (Denmark)

    Gao, Jingjing; Kørnøv, Lone; Christensen, Per

    Abstract: Indicators are widely used in SEA to measure, communicate and monitor impacts from a proposed policy, plan or programme, and can improve the effectiveness for the SEA by simplifying the complexity of both assessment and presentation. Indicators can be seen as part of the implementation...... process helping to understand, communicate and, integrate important environmental issues in planning and decision-making. On the other hand, use of indicators can also limit SEA effectiveness, if the ones chosen are biased or limited, if the aggregation gives incorrect interpretation...... and if the information requirement for different target groups is not addressed. Indicators are widely used in SEA to measure, communicate and monitor impacts from a proposed policy, plan or programme, and can improve the effectiveness for the SEA by simplifying the complexity of both assessment and presentation...

  4. Location-only satellite telemetry data for gray whales in the Bering and Chukchi Sea collected by Alaska Fisheries Science Center, National Marine Mammal Laboratory from 2012-08-25 to 2013-10-27 (NCEI Accession 0139361)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ARGOS location data (latitude and longitude in decimal format) and associated time (date and time) and location quality (as defined by Argos...

  5. Physical and meteorological data collected by shipboard ADCP and CTD, and moored meteorological buoy data collected in the Chukchi Sea from February 2007 to October 2013 by contractors for Shell, ConocoPhillips and Statoil (NODC Accession 0093399)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of a multi-year baseline environmental studies data set collected as part of the permitting process prior to drilling exploration wells. The...

  6. Visual surveys of cetaceans conducted in the Bering, Chukchi, and Beaufort Seas by Alaska Fisheries Science Center, National Marine Mammal Laboratory from 2010-08-25 to 2015-09-28 (NCEI Accession 0137906)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of several inter-agency agreements between the National Marine Mammal Laboratory (NMML) and the Bureau of Ocean Energy Management (BOEM), visual surveys of...

  7. Aerial Surveys of Arctic Marine Mammals (ASAMM) collected by National Marine Mammal Laboratory, Bureau of Ocean Energy Management, and other agencies in the Bering, Chukchi and Beaufort Seas (NODC Accession 0039614)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains aerial survey data from the surveys described below. The Bureau of Ocean Energy Management (BOEM), formerly the Minerals Management...

  8. Aerial surveys of bowhead and beluga whales along with incidental sighting of other marine mammals in the Bering, Beaufort and Chukchi Seas for the Bowhead Whale Aerial Survey Project (BWASP), 1979 - 2004 (NODC Accession 0001941)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  9. NOAA/EcoFOCI Chukchi Sea ADCP Mooring time-series data, stations C1, C2, and C3, 2010-08-29 to 2012-08-22, including zonal (U) and meridional (V) current measurements. (NCEI Accession 0149848)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These Acoustic Doppler Current Profiler (ADCP) time-series data sets, consist of zonal current (U) and meridional current (V) measurements from moored instruments at...

  10. AFSC/RACE/EcoFOCI - Ichthyoplankton data collected in support of FOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska 1972 to Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains records of fish eggs and larvae collected during FOCI assessment surveys. Records include all data pertinent to identify where specimens were...

  11. AFSC/RACE/EcoFOCI - Zooplankton data collected in support of FOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska, 1987 – Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data are abundance by taxanomic group (to species where possible), stage, size and sex. Zooplankton sorting is performed at The Polish Plankton Sorting...

  12. Aerial sightings of bowhead whales and other marine mammals by the US Department of the Interior's Minerals Management Service, 1979 - 2006, in the Bering, Chukchi and Beaufort Seas (NODC Accession 0014906)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  13. Dead sea water intoxication.

    Science.gov (United States)

    Levy-Khademi, Floris; Brooks, Rebecca; Maayan, Channa; Tenenbaum, Ariel; Wexler, Isaiah D

    2012-08-01

    Near drowning in the Dead Sea is associated with both respiratory manifestations and severe electrolyte abnormalities. It is often difficult to distinguish between the contributions of sea water aspiration or ingestion to clinical manifestations. We present a unique case of accidental ingestion of a large amount of Dead Sea water through a gastrostomy tube in which a patient with familial dysautonomia presented with severe electrolyte disturbances. Forced diuresis with large amounts of intravenous fluids resulted in clinical and biochemical improvement. Full recovery was achieved after 2 days of treatment.

  14. The north Sulu Sea productivity

    Science.gov (United States)

    Xiao, Z.

    2009-12-01

    The Sulu Sea is a part of the western North Pacific. It is a closed sea for its deep water and a semi-closed sea for its upper layer. The Sulu Sea exchanges mainly surface waters with the South China Sea and the Celebes Sea. The Sulu Sea is more productive than the adjacent South China Sea (Jones, 2002). On the basis of MERIS satellite observations from 2002 to 2008, we focus on the high-chlorophyll area as an indicator of the abundance of primary productivity in the Sulu Sea. Strong chlorophyll concentration in the north Sulu Sea close to the Mindoro Strait mainly occurs from December to March and low chlorophyll concentration happens in April to November. The adjacent South China Sea on the other side of Mindoro Strait has shown persistent signs of low chlorophyll concentration. Based on 1/8° Global Navy Coastal Ocean Model, the intrusion of the South China Sea waters through the Mindoro Strait to the Sulu Sea from April to November is the main reason for the low chlorophyll concentration observed in the north Sulu Sea. During April to November, the South China Sea waters flow through the Mindoro Strait and stay on the surface of the north Sulu Sea because of their low density. The north Sulu Sea waters mix with fresher waters coming from the South China Sea without new nutrients supply. When the inflow from South China Sea to Sulu Sea ceases in December to March, the upwelling due to the summer monsoon wind becomes an important mechanism supplying deep nutrients to the surface water which lead to high chlorophyll concentration. Jones, I.S.F., 2002. Primary production in the Sulu Sea. Proceedings of the Indian Academy of Sciences-Earth and Planetary Sciences 111, 209-213.

  15. Pollution of coastal seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    Pollution of various environments is a consequence of population growth and industrialisation. Coastal seas form part of marine environment and are very rich in minerals, crude oil fishes etc. They are also being used for disposal of wastes from...

  16. Arctic Sea Level Reconstruction

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    method.For oceanographic purposes, the altimetric record over the Arctic Ocean is inferiorin quality to that of moderate latitudes, but nonetheless an invaluable set of observations. During this project, newly processed Arctic altimetry from the ERS-1/-2 and Envisat missions has become available......Reconstruction of historical Arctic sea level is very difficult due to the limited coverage and quality of tide gauge and altimetry data in the area. This thesis addresses many of these issues, and discusses strategies to help achieve a stable and plausible reconstruction of Arctic sea level from...... 1950 to today.The primary record of historical sea level, on the order of several decades to a few centuries, is tide gauges. Tide gauge records from around the world are collected in the Permanent Service for Mean Sea Level (PSMSL) database, and includes data along the Arctic coasts. A reasonable...

  17. Sea Scallop Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Sea Scallop Survey began in 1980 and has covered an area from Cape Hatteras to Georges Bank. The survey aims to determine the distribution and...

  18. A Sea Floor Penetrometer.

    Science.gov (United States)

    processed through an analog-to-digital (A/D) converter, and stored in the memory of a mini-computer. Computer algorithms are applied to the deceleration data to provide real-time sea floor classification.

  19. South China Sea.

    Science.gov (United States)

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the

  20. South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Brian [Hong Kong Univ., Swire Inst. of Marine Science, Hong Kong (China); Hong Kong Univ., Dept. of Ecology and Biodiversity, Hong Kong (China); Blackmore, Graham [Hong Kong Univ. of Science and Technology, Dept. of Biology, Hong Kong (China)

    2001-07-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshops and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km{sup 2} and depths range from the shallowest coastal fringe to 5377m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economics on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken

  1. USACE Extreme Sea levels

    Science.gov (United States)

    2014-03-14

    flooding in the Thames Estuary under imaginable worst case sea-level rise scenarios. Int J Water Resour Dev Special Edition Water Disasters 21(4):577...Extreme tide and sea-level events. Technical report, Antarctic Climate and Ecosystems Corporate Research Centre. McMillan, A., Batstone, C...Barros V, Stocker TF, Qin D, Dokken DJ, Ebi KL, Mastrandrea MD, Mach KJ, Plattner GK, Allen SK, Tignor M, Midgley PM. A Special Report of Working Groups

  2. Contemporary sea level rise.

    Science.gov (United States)

    Cazenave, Anny; Llovel, William

    2010-01-01

    Measuring sea level change and understanding its causes has considerably improved in the recent years, essentially because new in situ and remote sensing observations have become available. Here we report on most recent results on contemporary sea level rise. We first present sea level observations from tide gauges over the twentieth century and from satellite altimetry since the early 1990s. We next discuss the most recent progress made in quantifying the processes causing sea level change on timescales ranging from years to decades, i.e., thermal expansion of the oceans, land ice mass loss, and land water-storage change. We show that for the 1993-2007 time span, the sum of climate-related contributions (2.85 +/- 0.35 mm year(-1)) is only slightly less than altimetry-based sea level rise (3.3 +/- 0.4 mm year(-1)): approximately 30% of the observed rate of rise is due to ocean thermal expansion and approximately 55% results from land ice melt. Recent acceleration in glacier melting and ice mass loss from the ice sheets increases the latter contribution up to 80% for the past five years. We also review the main causes of regional variability in sea level trends: The dominant contribution results from nonuniform changes in ocean thermal expansion.

  3. Alaska Phocid Argos Telemetry Archive (2004-2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Polar Ecosystems Program conducts research and monitoring on phocid seals in the East Bering Sea, West Bering Sea, Gulf of Alaska, Beaufort Sea, and Chukchi Sea...

  4. Projecting future sea level

    Science.gov (United States)

    Cayan, Daniel R.; Bromirski, Peter; Hayhoe, Katharine; Tyree, Mary; Dettinger, Mike; Flick, Reinhard

    2006-01-01

    California’s coastal observations and global model projections indicate that California’s open coast and estuaries will experience increasing sea levels over the next century. Sea level rise has affected much of the coast of California, including the Southern California coast, the Central California open coast, and the San Francisco Bay and upper estuary. These trends, quantified from a small set of California tide gages, have ranged from 10–20 centimeters (cm) (3.9–7.9 inches) per century, quite similar to that estimated for global mean sea level. So far, there is little evidence that the rate of rise has accelerated, and the rate of rise at California tide gages has actually flattened since 1980, but projections suggest substantial sea level rise may occur over the next century. Climate change simulations project a substantial rate of global sea level rise over the next century due to thermal expansion as the oceans warm and runoff from melting land-based snow and ice accelerates. Sea level rise projected from the models increases with the amount of warming. Relative to sea levels in 2000, by the 2070–2099 period, sea level rise projections range from 11–54 cm (4.3–21 in) for simulations following the lower (B1) greenhouse gas (GHG) emissions scenario, from 14–61 cm (5.5–24 in) for the middle-upper (A2) emission scenario, and from 17–72 cm (6.7–28 in) for the highest (A1fi) scenario. In addition to relatively steady secular trends, sea levels along the California coast undergo shorter period variability above or below predicted tide levels and changes associated with long-term trends. These variations are caused by weather events and by seasonal to decadal climate fluctuations over the Pacific Ocean that in turn affect the Pacific coast. Highest coastal sea levels have occurred when winter storms and Pacific climate disturbances, such as El Niño, have coincided with high astronomical tides. This study considers a range of projected future

  5. 西北冰洋楚科奇海台08 P23孔氧同位素3期以来的古海洋与古气候记录%PALEOCEANOGRAPHIC AND PALEOCLIMATIC RECORDS OF CORE 08P23 FROM THE CHUKCHI PLATEAU, WESTERN ARCTIC OCEAN,SINCE MIS 3

    Institute of Scientific and Technical Information of China (English)

    章陶亮; 王汝建; 陈志华; 陈建芳; 程振波; 孙烨忱

    2014-01-01

    Multi-proxy investigations have been performed on core 08P23,which was collected from the Chukchi Plateau, western Arctic Ocean,during the third Chinese National Arctic Research Expedition.The core was dated to Marine Isotope Stage(MIS)3 by a combination of AMS 14 C dating and regional core correlation.A total of 5 prominent ice-rafted detritus(IRD)events were recognized in MIS 2 and MIS 3 .The IRD events in MIS 3 originated from the vast carbonate rock outcrops of the Canadian Arctic Archipelago and the clastic quartz in MIS 2 may have had a Eura-sian origin.Most -δ18 O and -δ13 C values of Neogloboquadrina pachyderma(sinistral)(Nps)in core 08P23 are lighter than the average values of the surface sediments.The light Nps-δ18 O and -δ13 C values in the two brown layers in MIS 1 and MIS 3 resulted from meltwater events,and those in the gray layers in MIS 3 were caused by enhanced sea ice formation.The Nps-δ18 O values vary inversely with those of Nps-δ13 C in MIS 2,indicating that the study area was covered by thick sea ice or an ice sheet with cold temperatures and little meltwater,which prevented bioproductivity and sea-atmosphere exchange,as well as water mass ventilation.The covarying light values of Nps-δ18 O and -δ13 C in MIS 1 and MIS 3 resulted from meltwater and/or brine rejection.%通过中国第三次北极科学考察在北冰洋楚科奇海台采集的08P23孔样品的多项指标分析以及与其他孔的沉积记录综合对比,将08P23孔沉积物初步分为氧同位素3期(MIS 3)-MIS 1的沉积序列。MIS 3以来,楚科奇海台08P23孔可以识别出5个显著的冰筏碎屑(Ice-Rafted Detritus,IRD)事件,分别出现在MIS 2和MIS 3。其中,MIS 3的IRD事件中碎屑碳酸盐岩主要来自于加拿大北极群岛分布广泛的古生代碳酸盐岩露头,MIS 2的IRD事件中碎屑石英可能来源于欧亚大陆边缘。该孔大部分层位浮游有孔虫左旋厚壁新方球虫Neogloboquadrina pachyderma

  6. The Dead Sea

    Science.gov (United States)

    2006-01-01

    The Dead Sea is the lowest point on Earth at 418 meters below sea level, and also one of the saltiest bodies of water on Earth with a salinity of about 300 parts-per-thousand (nine times greater than ocean salinity). It is located on the border between Jordan and Israel, and is fed by the Jordan River. The Dead Sea is located in the Dead Sea Rift, formed as a result of the Arabian tectonic plate moving northward away from the African Plate. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride. In the early part of the 20th century, the Dead Sea began to attract interest from chemists who deduced that the Sea was a natural deposit of potash and bromine. From the Dead Sea brine, Israel and Jordan produce 3.8 million tons potash, 200,000 tons elemental bromine, 45,000 tons caustic soda, 25, 000 tons magnesium metal, and sodium chloride. Both countries use extensive salt evaporation pans that have essentially diked the entire southern end of the Dead Sea. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining

  7. Dynamics of sea level variations in the coastal Red Sea

    Science.gov (United States)

    Churchill, James; Abulnaja, Yasser; Nellayaputhenpeedika, Mohammedali; Limeburner, Richard; Lentz, Steven

    2016-04-01

    Sea level variations in the central Red Sea coastal zone span a range of roughly 1.2 m. Though relatively small, these water level changes can significantly impact the environment over the shallow reef tops prevalent in the central Red Sea, altering the water depth by a factor or two or more. While considerable scientific work has been directed at tidal and seasonal variations of Red Sea water level, very little attention has been given to elevation changes in an 'intermediate' frequency band, with periods of 2-30 d, even though motions in this band account for roughly half of the sea level variance in central Red Sea. We examined the sea level signal in this band using AVISO sea level anomaly (SLA) data, COARDAS wind data and measurements from pressure sensors maintained for more than five years at a number of locations in Saudi Arabian coastal waters. Empirical orthogonal function analysis of the SLA data indicates that longer-period (10-30 d) sea level variations in the intermediate band are dominated by coherent motions in a single mode that extends over most of the Red Sea axis. Idealized model results indicate that this large-scale mode of sea level motion is principally due to variations in the large-scale gradient of the along-axis wind. Our analysis indicates that coastal sea level motions at shorter periods (2-10 d) are principally generated by a combination of direct forcing by the local wind stress and forcing associated with large-scale wind stress gradients. However, also contributing to coastal sea level variations in the intermediate frequency band are mesoscale eddies, which are prevalent throughout the Red Sea basin, have a sea level signal of 10's of cm and produce relatively small-scale (order 50 km) changes in coastal sea level.

  8. Air-sea exchange studies at the North Sea

    NARCIS (Netherlands)

    Leeuw, G. de; Eijk, A.M.J. van; Kunz, G.J.; Veefkind, P.J.

    1996-01-01

    The North Sea can be considered as a local 'inner' sea in which many processes are quite different from these over the open ocean. The surrounding land has a major influence, being the source for man-made aerosols and gases, whereas the North Sea acts as a sink for these. At the same time the North

  9. Seasonal Change of Steric Sea Level in the GIN Seas

    Institute of Scientific and Technical Information of China (English)

    LI Lei; WANG Huijuan; SUN Ruili

    2011-01-01

    The Greenland Sea, Iceland Sea, and Norwegian Sea (GIN seas) form the main channel connecting the Arctic Ocean with other Oceans, where significant water and energy exchange take place, and play an important role in global climate change. In this study steric sea level, associated with temperature and salinity, in the GIN seas is examined based on analysis of the monthly temperature and salinity fields from Polar science center Hydrographic Climatology (PHC3.0). A method proposed by Tabata et al. is used to calculate steric sea level, in which, steric sea level change due to thermal expansion and haline contraction is termed as the thermosteric component (TC) and the halosteric component (SC), recpectively. Total steric sea level (TSSL) change is the sum of TC and SC. The study shows that SC is making more contributions than TC to the seasonal change of TSSL in the Greenland Sea, whereas TC contributes more in the Norwegian and the Iceland Seas. Annual variation of TSSL is larger than 50ram over most regions of the GIN Seas, and can be larger than 200mm at some locations such as 308mm at 76.5°N, 12.5°E and 246mm at 77.50N, 17.5°W.

  10. Analysis of Sea Spikes in Radar Sea Clutter Data

    NARCIS (Netherlands)

    Melief, H.W.; Greidanus, H.; Genderen, P. van; Hoogeboom, P.

    2006-01-01

    Abstract—In this paper three sets of high-resolution, coherent, and polarimetric radar sea clutter data are analyzed and compared with radar sea clutter models. The nature of the data allows a thorough analysis of the power, polarization and velocity of the sea clutter. It is shown that these quanti

  11. What happened to gray whales during the Pleistocene? The ecological impact of sea-level change on benthic feeding areas in the North Pacific Ocean.

    Directory of Open Access Journals (Sweden)

    Nicholas D Pyenson

    Full Text Available BACKGROUND: Gray whales (Eschrichtius robustus undertake long migrations, from Baja California to Alaska, to feed on seasonally productive benthos of the Bering and Chukchi seas. The invertebrates that form their primary prey are restricted to shallow water environments, but global sea-level changes during the Pleistocene eliminated or reduced this critical habitat multiple times. Because the fossil record of gray whales is coincident with the onset of Northern Hemisphere glaciation, gray whales survived these massive changes to their feeding habitat, but it is unclear how. METHODOLOGY/PRINCIPAL FINDINGS: We reconstructed gray whale carrying capacity fluctuations during the past 120,000 years by quantifying gray whale feeding habitat availability using bathymetric data for the North Pacific Ocean, constrained by their maximum diving depth. We calculated carrying capacity based on modern estimates of metabolic demand, prey availability, and feeding duration; we also constrained our estimates to reflect current population size and account for glaciated and non-glaciated areas in the North Pacific. Our results show that key feeding areas eliminated by sea-level lowstands were not replaced by commensurate areas. Our reconstructions show that such reductions affected carrying capacity, and harmonic means of these fluctuations do not differ dramatically from genetic estimates of carrying capacity. CONCLUSIONS/SIGNIFICANCE: Assuming current carrying capacity estimates, Pleistocene glacial maxima may have created multiple, weak genetic bottlenecks, although the current temporal resolution of genetic datasets does not test for such signals. Our results do not, however, falsify molecular estimates of pre-whaling population size because those abundances would have been sufficient to survive the loss of major benthic feeding areas (i.e., the majority of the Bering Shelf during glacial maxima. We propose that gray whales survived the disappearance of their

  12. Atlantic Flyway Sea Duck Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Atlantic Flyway Sea Duck Survey, conducted from 1991 to 2002 by the U.S. Fish and Wildlife Service, was established to record sea duck numbers using near shore...

  13. SEA LEVEL (TOPEX/POSEIDON)

    Data.gov (United States)

    National Aeronautics and Space Administration — Sea level rise is caused by the thermal expansion of sea water due to climate warming and widespread melting of land ice. The TOPEX/POSEIDON mission a joint...

  14. Seafloor Control on Sea Ice

    Science.gov (United States)

    Nghiem, S. V.; Clemente-Colon, P.; Rigor, I. G.; Hall, D. K.; Neumann, G.

    2011-01-01

    The seafloor has a profound role in Arctic sea ice formation and seasonal evolution. Ocean bathymetry controls the distribution and mixing of warm and cold waters, which may originate from different sources, thereby dictating the pattern of sea ice on the ocean surface. Sea ice dynamics, forced by surface winds, are also guided by seafloor features in preferential directions. Here, satellite mapping of sea ice together with buoy measurements are used to reveal the bathymetric control on sea ice growth and dynamics. Bathymetric effects on sea ice formation are clearly observed in the conformation between sea ice patterns and bathymetric characteristics in the peripheral seas. Beyond local features, bathymetric control appears over extensive ice-prone regions across the Arctic Ocean. The large-scale conformation between bathymetry and patterns of different synoptic sea ice classes, including seasonal and perennial sea ice, is identified. An implication of the bathymetric influence is that the maximum extent of the total sea ice cover is relatively stable, as observed by scatterometer data in the decade of the 2000s, while the minimum ice extent has decreased drastically. Because of the geologic control, the sea ice cover can expand only as far as it reaches the seashore, the continental shelf break, or other pronounced bathymetric features in the peripheral seas. Since the seafloor does not change significantly for decades or centuries, sea ice patterns can be recurrent around certain bathymetric features, which, once identified, may help improve short-term forecast and seasonal outlook of the sea ice cover. Moreover, the seafloor can indirectly influence cloud cover by its control on sea ice distribution, which differentially modulates the latent heat flux through ice covered and open water areas.

  15. Wadden Sea Mud

    DEFF Research Database (Denmark)

    Møller-Jensen, P.

    The present thesis deals with the transport phenomena of estuarine cohesive sediment from a laboratory and a numerical point of view. The cohesive sediment used throughout the whole process was natural mud from the Danish part of the Wadden sea, Ho Bay. In the laboratory, the work was concentrated...

  16. Sailing the Cyber Sea

    Science.gov (United States)

    2012-04-01

    years, the Internet 4 years, and the iPod 3 years, while Facebook added 200 million users in less than 1 year. And finally, if Facebook were a... Apple ] gets an iPhone. It’s not an acceptable trade.” New Thinking In the context of security, unleashing the power of the Cyber Sea has changed

  17. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki

    2010-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radi...

  18. Pollution around Malta's sea

    OpenAIRE

    Formosa, Nicolette; Duca, Edward

    2014-01-01

    Marine littering is a global concern and every single year tons of litter end up in the ocean all around the globe. It has become such a problem that the waste has amalgamated into huge ‘islands’ floating in the world’s oceans. http://www.um.edu.mt/think/pollution-around-maltas-sea/

  19. Geochemical signatures of sediments documenting Arctic sea-ice and water mass export through Fram Strait since the Last Glacial Maximum

    Science.gov (United States)

    Maccali, Jenny; Hillaire-Marcel, Claude; Carignan, Jean; Reisberg, Laurie C.

    2013-03-01

    from several sources including northwestern Canada (Mackenzie River), the western Arctic, the East Siberian/Chukchi Seas, and the more proximal Greenland margin. The isotopic compositions of leachates are mostly linked to boundary exchange processes near major meltwater and freshwater source areas. Due to its longer residence time relative to Pb, Nd preserves the isotopic signature of more distal areas where high-density particulate fluxes may occur. In the studied core, Nd-isotope leachate data illustrate the influence of the western Russian margins prior to the YD event and that of the East Siberian and Chukchi Sea margins following this event. This study illustrates that complementary information on IRD sources and water-mass histories can be obtained from isotopic analyses of inherited (residual) and exchangeable (leachable) fractions in deep Arctic Ocean sediments. Higher resolution cores are now needed to illustrate more rapid variations of paleo sea-ice and water mass circulation.

  20. What Happens when Sea Ice Retreats, Peatlands Form, and a Landbridge Drowns? A Molecular View of the Last Deglacial from the Pacific-Arctic Gateway

    Science.gov (United States)

    Kocis, J. J.; Petsch, S.; Castañeda, I. S.; Brigham-Grette, J.

    2014-12-01

    Arctic peatlands and thermokarst lakes (TK) are thought to play a significant role in changing atmospheric methane concentration (AMC) during the last deglacial. However, there is debate concerning timing of their initiation and extent they drove variations in AMC. Models show sea ice cover (SIC) and sea surface temperatures (SSTs) can also play a significant role. Yet, changes in peatland/TK lake areal extent in response to those dynamics as continental shelves were submerged are often not considered. To examine such connections, we report on molecular proxies in marine records that reveal change in terrestrial organic matter (TOM) export, SIC, and SSTs as sea levels rose during the last 18 ka in the Pacific-Arctic Gateway. Here, TOM input to the ocean was tracked by measuring the flux of branched glycerol dialkyl glycerol tetraethers, n-alkyl lipids, and pentacyclic triterpenoids. SIC and SSTs were reconstructed using modern calibrations of highly branched isoprenoid alkene abundances in surface sediments from the Bering and Chukchi Seas. SSTs were also reconstructed based on the relative abundance of isoprenoid glycerol dialkyl glycerol tetraethers. Our sediment records reveal increased flux of TOM coincides with peatland/TK lake initiation, reduced SIC (~20%), and warmer SSTs (~4°C) as AMC increased during the Bølling-Allerød (BA). Terrestrial flux dramatically reduced as SIC increased (~50%) and SSTs cooled as AMC fell during the Younger Dryas. Most notably, TOM export rapidly rebounds as AMC abruptly rose throughout the Holocene Thermal Maximum (HTM), when SSTs warmed by ~3°C and SIC diminished and peatland areal extent increased. Using multi-proxy evidence in combination with a simple model that accounts for submergence of peatland/TK lake area, we estimate that the exposed Beringian shelf emitted an amount of CH4 comparable to previously reported peatland emissions in Alaska during the BA and HTM. The GDGT-based methane index (MI) was hydrates were not

  1. The North Sea - A shelf sea in the Anthropocene

    Science.gov (United States)

    Emeis, Kay-Christian; van Beusekom, Justus; Callies, Ulrich; Ebinghaus, Ralf; Kannen, Andreas; Kraus, Gerd; Kröncke, Ingrid; Lenhart, Hermann; Lorkowski, Ina; Matthias, Volker; Möllmann, Christian; Pätsch, Johannes; Scharfe, Mirco; Thomas, Helmuth; Weisse, Ralf; Zorita, Eduardo

    2015-01-01

    Global and regional change clearly affects the structure and functioning of ecosystems in shelf seas. However, complex interactions within the shelf seas hinder the identification and unambiguous attribution of observed changes to drivers. These include variability in the climate system, in ocean dynamics, in biogeochemistry, and in shelf sea resource exploitation in the widest sense by societies. Observational time series are commonly too short, and resolution, integration time, and complexity of models are often insufficient to unravel natural variability from anthropogenic perturbation. The North Sea is a shelf sea of the North Atlantic and is impacted by virtually all global and regional developments. Natural variability (from interannual to multidecadal time scales) as response to forcing in the North Atlantic is overlain by global trends (sea level, temperature, acidification) and alternating phases of direct human impacts and attempts to remedy those. Human intervention started some 1000 years ago (diking and associated loss of wetlands), expanded to near-coastal parts in the industrial revolution of the mid-19th century (river management, waste disposal in rivers), and greatly accelerated in the mid-1950s (eutrophication, pollution, fisheries). The North Sea is now a heavily regulated shelf sea, yet societal goals (good environmental status versus increased uses), demands for benefits and policies diverge increasingly. Likely, the southern North Sea will be re-zoned as riparian countries dedicate increasing sea space for offshore wind energy generation - with uncertain consequences for the system's environmental status. We review available observational and model data (predominantly from the southeastern North Sea region) to identify and describe effects of natural variability, of secular changes, and of human impacts on the North Sea ecosystem, and outline developments in the next decades in response to environmental legislation, and in response to

  2. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    a relationship between plunging jet particle ux, oceanic particle ux, and energy dissipation rate in both systems. Previous sea spray aerosol studies dissipate an order of magnitude more energy for the same particle ux production as the open ocean. A scaling factor related to the energy expended in air...... emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use...... jet in high concentrations of surface active organics and brackish water salinities. The jet produces particles with less cloud condensation activity, implying an increase in organic material in aerosol particles produced by the plunging jet over the frit. In the second paper we determine...

  3. Spatio-Temporal Variability of Arctic Sea Ice Extent and Its Numerical Analysis with Sea Surface Temperature and Air Temperature%北极海冰范围时空变化及其与海温气温间的数值分析

    Institute of Scientific and Technical Information of China (English)

    孔爱婷; 刘健; 余旭; 左菲

    2016-01-01

    GIS software. Then, the freezing and thawing processes of the sea ice were discussed in detail. The re-sults show that the Arctic sea ice mainly freezes and thaws in various marginal seas, including the Bering sea, Okhotsk, Beaufort Sea, Chukchi Sea, East Siberian Sea, Laptev Sea, Kara Sea, Barents Sea, Hudson B. and Baffin Bay. Finally, according to the sea surface temperature and air temperature data, the relationships among Arctic sea ice extent, sea surface temperature and air tempera-ture were preliminarily discussed here. The results show that a change of the Arctic sea ice which affects the sea surface tempera-ture may cause a variation of the air temperature. However, the seasonal changes of sea ice extent occur later than the seasonal changes of sea surface temperature and air temperature. The relationships among Arctic sea ice extent, sea surface temperature and air temperature in Chukotskoye More were analyzed using the sea surface temperature data and air temperature data derived from the ship-based observations. The data show that when the sea ice extent gets closer to the North Pole, the sea surface temperature and air temperature will be lower. When the sea ice extent gets closer to the land, the sea surface temperature and air temperature will be higher.

  4. Sea Basing Logistiek

    Science.gov (United States)

    2007-11-01

    iets wat nu voor zware goederen niet mogeljk is met de middelen binnen de Nederlandse krijgsmachit. Nederland heeft bijvoorbeeld (nog) geen specifieke...weer gevechtsklaar zijn. Nederlandse troepen voeren de reconstitute fase in het algemeen uit in Nederland . [Kang&Gue] A special concern in sea based...besluit Nederland zelf in te grijpen. De Nederlandse vredesmissie bevindt zich nabij de kust. maar ver van de grens met buurlanden. De operatie kan niet

  5. SEA/WOMAN

    OpenAIRE

    Furse, Anna F. D.

    2011-01-01

    A new laboratory research performance by Anna Furse, Athletes of the Heart, UK) in collaboration with Maja Mitic (DAH Teatar, Serbia) and Antonella Diana (Teatret OM, Denmark) based on Henrik Ibsen's 'The lady from the sea' (1888). The project is an AHRC/ACE funded project as part of the Pinter Centre for Performance and Creative Writing's Fractured Narratives project. It has been touring in the UK and to Beirut, Lebanon.

  6. SEA/WOMAN

    OpenAIRE

    Furse, Anna F. D.

    2011-01-01

    A new laboratory research performance by Anna Furse, Athletes of the Heart, UK) in collaboration with Maja Mitic (DAH Teatar, Serbia) and Antonella Diana (Teatret OM, Denmark) based on Henrik Ibsen's 'The lady from the sea' (1888).\\ud \\ud The project is an AHRC/ACE funded project as part of the Pinter Centre for Performance and Creative Writing's Fractured Narratives project. It has been touring in the UK and to Beirut, Lebanon.

  7. Dead Sea rhodopsins revisited.

    Science.gov (United States)

    Bodaker, Idan; Suzuki, Marcelino T; Oren, Aharon; Béjà, Oded

    2012-12-01

    The Dead Sea is a unique hypersaline ecosystem with near toxic magnesium levels (∼2 M), dominance of divalent cations and a slightly acidic pH. Previously, we reported a haloarchaeon related to Halobacterium salinarum to dominate in a microbial bloom that developed in 1992 in the upper water layers of the lake following massive freshwater runoff. Whether this clade also dominated an earlier bloom in 1980-1982 cannot be ascertained as no samples for cultivation-independent analysis were preserved. The presence of the light-driven proton pump bacteriorhodopsin was reported in the 1980-1982 bloom of prokaryotes that had developed in the Dead Sea. To test the hypothesis that bacteriorhodopsin proton pumping may play a major role in determining what type of haloarchaea may dominate in specific bloom conditions, we compared rhodopsin genes recovered from Dead Sea biomass collected in different periods with genes coding for retinal proteins in isolated haloarchaea. Novel bacteriorhodopsin and sensory rhodopsin genes were found in samples collected in 2007 and 2010. The fact that no rhodopsin genes were recovered from samples collected during the 1992 bloom, which was dominated by a single species, suggests that different clades were present in the 1980-1982 and 1992 blooms, and that bacteriorhodopsin proton pumping did not necessarily play a determinative role in the dominance of specific halophiles in the blooms.

  8. Bindin from a sea star

    OpenAIRE

    Patiño, Susana; Jan E. Aagaard; MacCoss, Michael J.; Swanson, Willie J.; Hart, Michael W

    2009-01-01

    The genetic basis for the evolution of development includes genes that encode proteins expressed on the surfaces of sperm and eggs. Previous studies of the sperm acrosomal protein bindin have helped to characterize the adaptive evolution of gamete compatibility and speciation in sea urchins. The absence of evidence for bindin expression in taxa other than the Echinoidea has limited such studies to sea urchins, and led to the suggestion that bindin might be a sea urchin-specific molecule. Here...

  9. Sea Salt Source Function over the Baltic Sea

    Science.gov (United States)

    Petelski, Tomasz; Makuch, Przemyslaw; Markuszewski, Piotr; Jankowski, Andrzej; Zieliński, Tymon

    2013-04-01

    Studies of production and transport of aerosol over the sea are very important for many areas of knowledge. Marine aerosol emitted from the sea surface helps to clean the boundary layer from other aerosol particles. The emitted droplets do not dry out in the highly humid surface layer air and because of their sizes most of them are deposited quickly at the sea surface. Therefore, marine aerosol has many features of rain i.e. the deposition in the marine boundary layer in high wind events is controlled not only by the "dry" processes but also by the "wet" scavenging. While many cruises conducted on board S/Y Oceania, we collected many data which were used to calculate sea salt source function over the Baltic Sea. Our cruises held between 2009 and 2012. Measurements were carried out using gradient method. For this method we used Laser Particle Counter (PMS model CSASP-100_HV) placed on one oft the mast of S/Y Oceania. Measurements were performed on five different levels around sea level: 8, 11, 14, 17 and 20 meters. Based on the averaged vertical concentration, profiles were calculated, using Monin-Obuchow theory, vertical sea spray fluxes in the near water layer. Based on fluxes calculated from vertical concentration profiles was calculated sea salt source function over the Baltic Sea. This function gives emission for different particle size, depending on environmental parameters. Emission of sea spray depends of the size of energy lost by the wind waves in process of collapse. Acknowledgements: The support for this study was provided by the project Satellite Monitoring of the Baltic Sea Environment - SatBałtyk founded by European Union through European Regional Development Fund contract No. POIG 01.01.02-22-011/09.

  10. Waves in the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    to watch. M. J. VARKEY sheds light on how these waves are formed SCIENCE REPORTER [9] MAY 1996 BIMAN BASU OU are on a seashore on a windless day. Watch the sea for some time and you will see regular, long waves run- ning towards the land, steepening... to special sand and wind structures SCIENCE REPORTER [10] MAY 1996 into active role. For a clear un- derstanding of the mechanisms of wave formation it is neces- sary to know some basic as- pects of wind as it blows over the water with low or high ve...

  11. NOAA NDBC SOS - sea_floor_depth_below_sea_surface

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have sea_floor_depth_below_sea_surface data. Because of the nature of SOS...

  12. EASE-Grid Sea Ice Age

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides weekly estimates of sea ice age for the Arctic Ocean from remotely sensed sea ice motion and sea ice extent. The ice age data are derived from...

  13. Sea modeling and rendering

    Science.gov (United States)

    Cathala, Thierry; Latger, Jean

    2010-10-01

    More and more defence and civil applications require simulation of marine synthetic environment. Currently, the "Future Anti-Surface-Guided-Weapon" (FASGW) or "anti-navire léger" (ANL) missile needs this kind of modelling. This paper presents a set of technical enhancement of the SE-Workbench that aim at better representing the sea profile and the interaction with targets. The operational scenario variability is a key criterion: the generic geographical area (e.g. Persian Gulf, coast of Somalia,...), the type of situation (e.g. peace keeping, peace enforcement, anti-piracy, drug interdiction,...)., the objectives (political, strategic, or military objectives), the description of the mission(s) (e.g. antipiracy) and operation(s) (e.g. surveillance and reconnaissance, escort, convoying) to achieve the objectives, the type of environment (Weather, Time of day, Geography [coastlines, islands, hills/mountains]). The paper insists on several points such as the dual rendering using either ray tracing [and the GP GPU optimization] or rasterization [and GPU shaders optimization], the modelling of sea-surface based on hypertextures and shaders, the wakes modelling, the buoyancy models for targets, the interaction of coast and littoral, the dielectric infrared modelling of water material.

  14. 北极航道相关海域科学考察研究进展%THE PROGRESS OF EXPEDITIONS AND RESEARCH IN THE SEAS RELATED TO THE ARCTIC PASSAGES

    Institute of Scientific and Technical Information of China (English)

    何剑锋; 吴荣荣; 张芳; 王勇; 俞勇

    2012-01-01

    中国从1999年开始至今已实施了四次北极科学考察,对白令海、楚科奇海、波弗特海、加拿大海盆和马卡若夫海盆进行了广泛的考察.全球变化致使北冰洋夏季海冰覆盖面积不断减少,导致冰期以来北极东北航道和西北航道的首次同时开通.北极航道集中在陆架区,不仅是海冰变化最为显著的海域,同时也是陆地-北冰洋相互作用最为显著的区域,对北冰洋区域气候、生态系统和生物多样性、经济和当地土著居民生活产生重大影响.本文对北极航道关键海域近年来国际相关科学考察进行了总结,对科学考察背后的各国北极策略进行分析,并从科学需求的角度对今后中国北极科学考察中针对北极航道相关海域应开展的科学考察与研究提出了相关建议.%Since 1999, China has undertaken four Arctic expeditions to the Bering Sea, the Chukchi Sea, the Beaufort Sea, the Canade Basin and the Makarov Basin. Global climate change has caused a decline in sea ice coverage in the Arctic Ocean in summer, leading to the opening of the Northeast and Northwest Passages. The Arctic shelf seas, where the passages are located, are not only the ares with the most significant sea ice changes, but are also the areas with the most significant land-ocean interactions. Sea ics changes have significant impact on the Arctic regional climate, ecosystems and biodiversity, and the local economy and indigenous people. This study summarizes the scientific investigations in the main area of the Arctic passages in recent years and provides comments on future Chinese Arctic cruises in the passage area form the viewpoint of scientific research.

  15. The Law of the Sea

    Science.gov (United States)

    Levy, Jean-Pierre

    1978-01-01

    Recounts problems related to the law of the sea and suggests that these problems could be dealt with in the classroom in an interdisciplinary manner. Problems include pollution control, fishing rights, development of deep sea mineral deposits, and shore access. (Author/DB)

  16. The environmental state at sea

    NARCIS (Netherlands)

    Tatenhove, van J.P.M.

    2016-01-01

    Seas and oceans are confronted with a plethora of environmental problems, caused by land-based activities (agriculture, industries, and ports) and by maritime activities (such as shipping, fishing, oil and gas drilling, tourism, and navigational dredging). Environmental problems at sea challenge the

  17. Her Husband Is at Sea

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    Out in the sea of China are Chinese offshore oil workers. They battle against wind, waves, loneliness and monotony. Their profession requires not only bravery and endurance from the employees themselves, but also from their spouses. It is because of the wives’support that the husbands can work at sea. This,for women, means double family responsibilities, loneliness, worries and endless waiting.

  18. Plastic in North Sea Fish

    NARCIS (Netherlands)

    Foekema, E.M.; Gruijter, de C.; Mergia, M.T.; Franeker, van J.A.; Murk, A.J.; Koelmans, A.A.

    2013-01-01

    To quantify the occurrence of ingested plastic in fish species caught at different geographical positions in the North Sea, and to test whether the fish condition is affected by ingestion of plastics, 1203 individual fish of seven common North Sea species were investigated: herring, gray gurnard, wh

  19. SeaPort-e Workshop

    Science.gov (United States)

    2014-08-01

    aquilent.com 22 QUESTIONS?? 23 Back-up 24 Program Evolution Category SeaPort Original (2001 – 2004) SeaPort-Enhanced (2004...Function = Industry User Function External System Interfaces: Create Purchase Request (Navy ERP ) Receive CAR Data (FPDS-NG) Receive Award Documents (EDA) Receive Award Data (SPS)

  20. Arctic Sea Ice Predictability and the Sea Ice Prediction Network

    Science.gov (United States)

    Wiggins, H. V.; Stroeve, J. C.

    2014-12-01

    Drastic reductions in Arctic sea ice cover have increased the demand for Arctic sea ice predictions by a range of stakeholders, including local communities, resource managers, industry and the public. The science of sea-ice prediction has been challenged to keep up with these developments. Efforts such as the SEARCH Sea Ice Outlook (SIO; http://www.arcus.org/sipn/sea-ice-outlook) and the Sea Ice for Walrus Outlook have provided a forum for the international sea-ice prediction and observing community to explore and compare different approaches. The SIO, originally organized by the Study of Environmental Change (SEARCH), is now managed by the new Sea Ice Prediction Network (SIPN), which is building a collaborative network of scientists and stakeholders to improve arctic sea ice prediction. The SIO synthesizes predictions from a variety of methods, including heuristic and from a statistical and/or dynamical model. In a recent study, SIO data from 2008 to 2013 were analyzed. The analysis revealed that in some years the predictions were very successful, in other years they were not. Years that were anomalous compared to the long-term trend have proven more difficult to predict, regardless of which method was employed. This year, in response to feedback from users and contributors to the SIO, several enhancements have been made to the SIO reports. One is to encourage contributors to provide spatial probability maps of sea ice cover in September and the first day each location becomes ice-free; these are an example of subseasonal to seasonal, local-scale predictions. Another enhancement is a separate analysis of the modeling contributions. In the June 2014 SIO report, 10 of 28 outlooks were produced from models that explicitly simulate sea ice from dynamic-thermodynamic sea ice models. Half of the models included fully-coupled (atmosphere, ice, and ocean) models that additionally employ data assimilation. Both of these subsets (models and coupled models with data

  1. Sea Surface Temperature Climate Data Record for the North Sea and Baltic Sea

    DEFF Research Database (Denmark)

    Høyer, Jacob L.; Karagali, Ioanna

    2016-01-01

    A 30-yr climate data record (CDR) of sea surface temperature (SST) has been produced with daily gap-free analysis fields for the North Sea and the Baltic Sea region from 1982 to 2012 by combining the Pathfinder AVHRR satellite data record with the Along-Track Scanning Radiometer (ATSR) Reprocessing...... observations on average. Validation against independent in situ observations shows a very stable performance of the data record, with a mean difference of -0.06 °C compared to moored buoys and a 0.46 °C standard deviation of the differences. The mean annual biases of the SST CDR are small for all years......, with a negligible temporal trend when compared against drifting and moored buoys. Analysis of the SST CDR reveals that the monthly anomalies for the North Sea, the Danish straits, and the central Baltic Sea regions show a high degree of correlation for interannual and decadal time scales, whereas the monthly...

  2. Role of sea ice in air-sea exchange and its relation to sea fog

    Institute of Scientific and Technical Information of China (English)

    解思梅; 包澄澜; 姜德中; 邹斌

    2001-01-01

    Synchronous or quasi-synchronous stereoscopic sea-ice-air comprehensive observation was conducted during the First China Arctic Expedition in summer of 1999. Based on these data, the role of sea ice in sea-air exchange was studied. The study shows that the kinds, distribution and thickness of sea ice and their variation significantly influence the air-sea heat exchange. In floating ice area, the heat momentum transferred from ocean to atmosphere is in form of latent heat; latent heat flux is closely related to floating ice concentration; if floating ice is less, the heat flux would be larger. Latent heat flux is about 21 23.6 W*m-2, which is greater than sensible heat flux. On ice field or giant floating ice, heat momentum transferred from atmosphere to sea ice or snow surface is in form of sensible heat. In the floating ice area or polynya, sea-air exchange is the most active, and also the most sensible for climate. Also this area is the most important condition for the creation of Arctic vapor fog. The heat exchange of a large-scale vapor fog process of about 500000 km2 on Aug. 21 22,1999 was calculated; the heat momentum transferred from ocean to air was about 14.8×109 kW. There are various kinds of sea fog, radiation fog, vapor fog and advection fog, forming in the Arctic Ocean in summer. One important cause is the existence of sea ice and its resultant complexity of both underlying surface and sea-air exchange.

  3. Sea truth validation of sea WiFS ocean colour sensor in the coastal waters of the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Desa, E.S.; Suresh, T.; Matondkar, S.G.P.; Desa, E.

    Sea will underestimate chlorophyll by up to 30%. Comparison of our in situ normalized water-leaving radiance [Lwn] and chlorophyll measurements at sea with that derived from the SeaWifs colour sensor shows that SeaWifs overestimates both Lwn...

  4. Sea surface temperature anomalies in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.

    . Further analysis has shown that the sea surface anomalies are well correlated to the anomalies of air temperature and latent heat flux values; whereas they are least correlated to the anomalies of wind stress and net radiation values, except over...

  5. Iridium in sea-water.

    Science.gov (United States)

    Fresco, J; Weiss, H V; Phillips, R B; Askeland, R A

    1985-08-01

    Iridium in sea-water has been measured (after isolation from the saline matrix by reduction with magnesium) by neutron bombardment, radiochemical purification and high-resolution gamma-ray spectroscopy. The concentration obtained in a Pacific coastal water was 1.02 +/- 0.26 x 10(-14) g per g of sea-water. At such extremely low concentrations, seawater is an extremely unlikely source for anomalously high iridium concentrations measured in the Cretaceous-Tertiary boundary layer of deep-sea sediments.

  6. Iridium in sea-water

    Energy Technology Data Exchange (ETDEWEB)

    Fresco, J.; Weiss, H.V.; Phillips, R.B.; Askeland, R.A.

    1985-08-01

    Iridium in sea-water has been measured (after isolation from the saline matrix by reduction with magnesium) by neutron bombardment, radiochemical purification and high resolution ..gamma..-ray spectroscopy. The concentration obtained in a Pacific coastal water was 1.02 +- 0.26 x 10/sup 14/ g per g of sea-water. At such extremely low concentrations, seawater is an extremely unlikely source for anomalously high iridium concentrations measured in the Cretaceous-Tertiary boundary layer of deep-sea sediments.

  7. Is sea-level rising?

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    be converted into sea level height by using the hydrostatic equation. Radar gauge uses a radar sensor, kept at a height looking down the sea, sends out a pulse of radio waves and measures the travel time to be reflected off the surface and back... to the sensor. By using the travel time and the speed of radio waves one can estimate the sea surface height. The tide gauge data have been analysed and used to predict the time of ‘high tide’ and ‘low tide’, which are used by ships to decide the timing...

  8. SMOS Sea Surface Salinity Validation in the South China Sea

    Science.gov (United States)

    Ren, Yongzheng; Li, Xiaoming; Dong, Qing

    2013-01-01

    In November 2009, the European Space Agency (ESA) launched the first soil moisture and ocean salinity (SMOS) satellite, which represented the first use of spaceborne remote sensing tools to probe global sea surface salinity (SSS). The SMOS satellite carries a microwave imaging radiometer with aperture synthesis (MIRAS) for detection in the microwave L-band as the only payload. The MIRAS instrument is expected to provide a global SSS distribution with a spatial resolution of approximately 100 km and an accuracy of 0.1-0.2 practical salinity units (psu). The South China Sea is semi-enclosed, and the sea conditions are relatively complex. The suitability of ESA SMOS salinity products for the South China Sea has not been validated. Therefore, using SSS data measured during an expedition in the South China Sea, which was sponsored by China Natural Science Foundation and conducted in the fall of 2011, this paper validated the SSS products released by ESA, which were retrieved using three sea surface roughness models. To analyze the effect of the spatial resolution on the weekly average SMOS SSS distribution, the weekly average salinity data were averaged to reduce the spatial resolution to 0.25 ° x 0.25°. These average data were then compared to the measured data, followed by an analysis of the error variation. In addition, the effects of the orbital track (ascending or descending) on the SSS retrieval were analyzed.

  9. Spirulina culture in sea water

    Energy Technology Data Exchange (ETDEWEB)

    Materassi, R.; Tredici, M.; Waldemaro, B.

    1984-01-01

    Laboratory experiments using small raceway ponds have shown that Spirulina maxima can be adapted easily to grow in sea-water supplemented with nitrate, phosphate, bicarbonate, and Fe-EDTA. To prevent precipitate formation, phosphate was supplied by diffusion through a dialysis membrane; the amount of Na-bicarbonate added was low (100 ppm) and the pH was kept in the range 8.6 - 8.8 by bubbling CO/sub 2/ into the culture. No significant differences have been noticed in productivity or in the chemical composition of the biomass between cultures in sea-water and in the standard bicarbonate medium. Cultures subjected to light/dark cycles of 12/12 hours showed a higher respiration rate in sea-water than in the bicarbonate medium. The higher weight loss in the sea-water medium in the dark was counterbalanced by an increased synthesis of carbohydrates during the light period. 9 references.

  10. Doppler characteristics of sea clutter.

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, Ann Marie; Doerry, Armin Walter

    2010-06-01

    Doppler radars can distinguish targets from clutter if the target's velocity along the radar line of sight is beyond that of the clutter. Some targets of interest may have a Doppler shift similar to that of clutter. The nature of sea clutter is different in the clutter and exo-clutter regions. This behavior requires special consideration regarding where a radar can expect to find sea-clutter returns in Doppler space and what detection algorithms are most appropriate to help mitigate false alarms and increase probability of detection of a target. This paper studies the existing state-of-the-art in the understanding of Doppler characteristics of sea clutter and scattering from the ocean to better understand the design and performance choices of a radar in differentiating targets from clutter under prevailing sea conditions.

  11. Sea otter studies in Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The final objective of the present Fish and Wildlife sea otter program is to learn enough of the ecology, population, reproductive potential, and requirements in...

  12. A Can of Sea Worms

    Science.gov (United States)

    Zinn, Donald J.

    1977-01-01

    A comprehensive discussion of the free-living worms that inhabit the beaches and subtidal bottoms of the Cape Cod shoreline is presented. Methods for the location, collection, preservation, and identification of sea worms are identified. (BT)

  13. Black Sea Bass genetic connectivity

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Microsatellite analysis of black sea bass was undertaken to determine magnitude and direction of mixing of black seabass across the Hatteras boundary, as well as...

  14. Towards Good Order at Sea

    DEFF Research Database (Denmark)

    Mandrup, Thomas; Vreÿ, Francois

    . The problems originating from the resultant “bad order at sea” can be directly felt on land, when smuggling, terrorism and related criminal activities operate more or less unhindered. The book provides an important mapping of the challenges preventing good order at sea off the African coast and East Africa......This book addresses a timely and important theme in the debate on how to create good governance at sea in general, but specifically in the Western Indian Ocean. In a security milieu where the number of piracy attacks originating from Somalia has decreased, there is an urgent need to address...... structural problems facing attempts to create and maintain good order at sea off East Africa. As mentioned in one of the chapters, the most secure place for a criminal in East Africa to be is at sea, because most African littoral states have only limited capacity to police their territorial waters...

  15. Sea bed mapping and inspection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference has 24 presentations on the topics: Sea bed mapping, inspection, positioning, hydrography, marine archaeology, remote operation vehicles and computerized simulation technologies, oil field activities and plans, technological experiences and problems. (tk)

  16. 2013年北极最小海冰范围比2012年增加的原因分析%Reasons for the increase minimum Arctic sea ice extent in 2013 compared with 2012

    Institute of Scientific and Technical Information of China (English)

    崔红艳; 乔方利; 舒启

    2015-01-01

    北极海冰范围从1979年有卫星观测资料以来呈现明显下降趋势,尤其是9月份。2012年9月北极海冰范围达到有观测记录以来的最小值,而2013年9月比2012年同期增加了60%。增加的区域主要在东西伯利亚海区、楚科奇海和波弗特海区。本文应用距平和经验模态分解方法,分析了美国国家冰雪数据中心的北极海冰卫星数据、欧洲预报中心的夏季底层大气环流数据和上层海洋的温度,指出2013年北极最小海冰范围比2012年在北冰洋太平洋扇区增加的原因,是由于表面气温(SAT )降低、海平面气压(SLP)升高、气旋式风场异常、表面空气中水汽含量(SH)降低以及海表面温度(SST)降低5个条件形成的冰-SAT 、冰-SST 和冰-汽(SH)3个正反馈机制共同作用造成的。%Satellite data since 1979 show that the monthly mean Arctic sea-ice extent has downward trends,with the largest trend in September.The Arctic sea-ice minimum extent is observed in September 2012.While the mini-mum Arctic sea-ice area in the following September 2013 increases 60% compared with 2012.The sea-ice increase areas mainly locate in the Pacific section of Arctic Ocean:East Siberian Sea,Chukchi Sea,and Beaufort Sea.By u-sing methods of climatological anomalies and Empirical Mode Decomposition,we investigated the Arctic sea-ice data from the National Snow and Ice Data Center,lower atmospheric circulation pattern and the upper-ocean from ERA-Interim data in summer to explain this sea-ice sharp increase phenomenon.Results show that the increasing of the Arctic sea ice in 2013 compared with 2012 is related to the following five conditions:the surface air temperature (SAT )decrease,sea level pressure (SLP)increase,the cyclonic anomaly of wind field,surface special humidity (SH)and surface sea temperature (SST)decrease.All these five favorable conditions for sea-ice increase are close-ly related with by the ice

  17. Dynamic Topography of the Bering Sea

    Science.gov (United States)

    2011-01-01

    Bering Sea. Comparisons also indicate that MDT estimates derived from the latest Gravity Recovery and Climate Experiment geoid model have more in common...with the presented sea surface topography than with the MDTs based on earlier versions of the geoid . The presented MDT will increase the accuracy of...estimating the geoid in the Bering Sea. 15. SUBJECT TERMS dynamic topography, sea surface height, Bering Sea, 4DVar 16. SECURITY CLASSIFICATION OF: a

  18. Alien seas oceans in space

    CERN Document Server

    Lopes, Rosaly

    2013-01-01

    In the early days of planetary observation, oceans were thought to exist in all corners of the Solar System. Carbonated seas percolated beneath the clouds of Venus. Features on the Moon's surface were given names such as "the Bay of Rainbows” and the "Ocean of Storms." With the advent of modern telescopes and spacecraft exploration these ancient concepts of planetary seas have been replaced by the reality of something even more exotic. Alien Seas serves up the current research, past beliefs, and new theories to offer a rich array of the "seas" on other worlds. It is organized by location and by the material composing the oceans under discussion, with expert authors penning chapters on their  specialty. Each chapter features new original art depicting alien seas, as well as the latest ground-based and spacecraft images. With the contributors as guides, readers can explore the wild seas of Jupiter's watery satellite Europa, believed similar in composition to battery acid. Saturn's planet-sized moon Titan see...

  19. Alaska Maritime National Wildlife Refuge : Annual narrative report : Calendar year 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Alaska Maritime NWR (including the Alaska Peninsula Unit, the Aleutian Islands Unit, the Bering Sea Unit, the Chukchi Sea Unit, and...

  20. Environmental properties and microbial communities in coastal waters of Barrow, Alaska from July 11, 2007 to January 14, 2009 (NODC Accession 0073540)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data set consists of basic water column properties of the Beaufort Sea and the Chukchi Sea near Barrow, Alaska. The environmental properties include salinity,...

  1. Chemical and isotopic tracers and other data from the Arctic Ocean from 1990-01-01 to 1999-12-31 (NCEI Accession 0068667)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are water column and sediment data largely collected in the Bering and Chukchi Seas, with some coverage for the Beaufort and East Siberian Seas, and with...

  2. Alaska Maritime National Wildlife Refuge : Annual narrative report : Calendar year 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Alaska Maritime NWR (including the Alaska Peninsula Unit, the Aleutian Islands Unit, the Bering Sea Unit, the Chukchi Sea Unit, and...

  3. Alaska Maritime National Wildlife Refuge : Annual narrative report : Calendar year 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Alaska Maritime NWR (including the Alaska Peninsula Unit, the Aleutian Islands Unit, the Bering Sea Unit, the Chukchi Sea Unit, and...

  4. Sea otter investigation, Amchitka Island, 1954, and proposed plan of research for sea otters

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report describes a sea otter investigation on Amchitka Island during 1954 and a proposed plan of research for sea otters. The report covers capturing wild sea...

  5. Deep-sea Hexactinellida (Porifera) of the Weddell Sea

    Science.gov (United States)

    Janussen, Dorte; Tabachnick, Konstantin R.; Tendal, Ole S.

    2004-07-01

    New Hexactinellida from the deep Weddel Sea are described. This moderately diverse hexactinellid fauna includes 14 species belonging to 12 genera, of which five species and one subgenus are new to science: Periphragella antarctica n. sp., Holascus pseudostellatus n. sp., Caulophacus (Caulophacus) discohexactinus n. sp., C. ( Caulodiscus) brandti n. sp., C. ( Oxydiscus) weddelli n. sp., and C. ( Oxydiscus) n. subgen. So far, 20 hexactinellid species have been reported from the deep Weddell Sea, 15 are known from the northern part and 10 only from here, while 10 came from the southern area, and five of these only from there. However, this apparent high "endemism" of Antarctic hexactinellid sponges is most likely the result of severe undersampling of the deep-sea fauna. We find no reason to believe that a division between an oceanic and a more continental group of species exists. The current poor database indicates that a substantial part of the deep hexactinellid fauna of the Weddell Sea is shared with other deep-sea regions, but it does not indicate a special biogeographic relationship with any other ocean.

  6. Toxic Algae and Early Warning Management in Yellow Sea and Bohai Sea of China

    Institute of Scientific and Technical Information of China (English)

    Song; Lun; Song; Guangjun; Song; Yonggang; Xu; Xiaohong

    2014-01-01

    The research status of toxic algae in Yellow Sea and Bohai Sea are reviewed from the aspects of toxicity characteristics,toxic mechanism and early warning management,and the existing toxic algae and their toxicity in Yellow Sea and Bohai Sea are analyzed in the paper. The early warning level of toxic algae in Yellow Sea and Bohai Sea of China is put forward,and the research direction of shellfish poisoning in future is summarized.

  7. Magnetohydrodynamic sea water propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Petrick, M.; Thomas, A.; Genens, L.; Libera, J.; Nietert, R.; Bouillard, J.; Pierson, E.; Hill, D.; Picologlou, B.; Ohlsson, O.; Kasprzyk, T.; Berry, G.

    1991-01-01

    An experimental and theoretical investigation of a large scale MHD propulsor has been undertaken whose objectives are to (1) investigate the transient and steady state performance of the thruster over operating parameter ranges that are compatible with achievement of high efficiency, (2) to quantify the principal loss mechanisms within the thruster and (3) to obtain preliminary hydroacoustic data. The performance of the thruster was first investigated theoretically with a 3-D code to quantify the loss mechanisms and identify experimental parameter ranges of interest. The loss mechanisms of interest are ohmic losses within the channel and those resulting from electrical currents at the entrance and exit of the thruster, and enhanced frictional losses. The analysis indicated that the relative importance of the loss mechanisms was a function of the thruster design and operating parameters. The experimental investigation of the large scale propulsor is being conducted on a sea water test facility that was designed to match the capabilities of a large 6-T superconducting magnet. The facility design was such that {approximately}90{degrees} of all losses occurred within the propulsion test train (inlet nozzle, propulsor and diffuser) thus facilitating isolation of the loss mechanisms. The test thruster itself is heavily instrumented to provide local measurements of velocity, pressure, and electric fields. The predicted overall thruster performance and value of the loss mechanisms will be compared with measured values. Comparisons will also be presented of the voltage gradients between electrodes, overall thruster efficiency, axial pressure gradients across the propulsor, change in velocity profiles, axial and vertical current distributions and exit distribution of the electrolytic gases.

  8. Magnetohydrodynamic sea water propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Petrick, M.; Thomas, A.; Genens, L.; Libera, J.; Nietert, R.; Bouillard, J.; Pierson, E.; Hill, D.; Picologlou, B.; Ohlsson, O.; Kasprzyk, T.; Berry, G.

    1991-12-31

    An experimental and theoretical investigation of a large scale MHD propulsor has been undertaken whose objectives are to (1) investigate the transient and steady state performance of the thruster over operating parameter ranges that are compatible with achievement of high efficiency, (2) to quantify the principal loss mechanisms within the thruster and (3) to obtain preliminary hydroacoustic data. The performance of the thruster was first investigated theoretically with a 3-D code to quantify the loss mechanisms and identify experimental parameter ranges of interest. The loss mechanisms of interest are ohmic losses within the channel and those resulting from electrical currents at the entrance and exit of the thruster, and enhanced frictional losses. The analysis indicated that the relative importance of the loss mechanisms was a function of the thruster design and operating parameters. The experimental investigation of the large scale propulsor is being conducted on a sea water test facility that was designed to match the capabilities of a large 6-T superconducting magnet. The facility design was such that {approximately}90{degrees} of all losses occurred within the propulsion test train (inlet nozzle, propulsor and diffuser) thus facilitating isolation of the loss mechanisms. The test thruster itself is heavily instrumented to provide local measurements of velocity, pressure, and electric fields. The predicted overall thruster performance and value of the loss mechanisms will be compared with measured values. Comparisons will also be presented of the voltage gradients between electrodes, overall thruster efficiency, axial pressure gradients across the propulsor, change in velocity profiles, axial and vertical current distributions and exit distribution of the electrolytic gases.

  9. Dead sea asphalts: historical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, A.

    1978-05-01

    Asphalts are present in the Dead Sea basin in three forms: (1) huge blocks, up to 100 tons in weight, composed of extremely pure (>99.99%) solid asphalt occasionally found floating on the lake, (2) veins, seepages, and cavity and fissure fillings in Lower Cretaceous to Holocene rocks, and (3) ozocerite veins on the eastern shore of the lake. Dead Sea asphalts probably have been documented over a longer period of time than any other hydrocarbon deposit--from antiquity to the 19th century. Major uses of asphalt from the Dead Sea have been as an ingredient in the embalming process, for medicinal purposes, for fumigation, and for agriculture. The first known war for control of a hydrocarbon deposit was in the Dead Sea area in 312 B.C. between the Seleucid Syrians and the Nabatean Arabs who lived around the lake. Surface manifestations of asphalt are linked closely to tectonic activity. In the lake itself, the asphalt is associated with diapirs During certain historic periods, tectonic and diapiric activity caused frequent liberation to the Dead Sea surface of semiliquid asphalt associated with large amounts of hydrogen sulfide gas. When the tectonic activity was attenuated, as in the 19th and 20th centuries, the rate of asphalt seepage to the bottom sediments of the Dead Sea was much slower and the asphalt solidified on the lake bottom. The release of asphalt to the surface became much more sporadic, and may have resulted in part from earthquakes. Thus, future asphalt prospecting in the Dead Sea area should be conducted along the boundaries of diapirs or their associated faults.

  10. The Increase of the Ice-free Season as Further Indication of the Rapid Decline of the Arctic sea ice

    Science.gov (United States)

    Rodrigues, J.

    2008-12-01

    level. For example, the Northwest Passage and the Northern Sea Route are especially relevant to assess the maritime transport between the Atlantic and the Pacific, changes in the ice cover in oil rich areas such as the north coast of Alaska will attract the attention of the oil industry, and the disappearance of the sea ice in Hudson Bay will strongly affect its wildlife. We divided the Arctic in 85 regions and examined how the LIFS and the ISII changed in each of them since 1979. 53 regions enjoyed their longest ice-free seasons in 2006 or 2007. 2006 was special for the Canadian Arctic (longest ice-free season on record for about half of the regions) while 2007 was the year of the Russian Arctic (with the longest ice-free season in the period under study for more than half of the regions). Some of the largest variations were observed in the Russian Arctic, where the average LIFS increased from 84 days in the late 1970s to 129 around 2006, to reach a maximum of 171 days in 2007. Let us quote the changes in the White Sea (105 days between 1979 and 2006), in the South Barents Sea (70 days), in the South East Siberian Sea (60 days) and in the mid-latitude Chukchi Sea (66 days). Other areas where important changes took place include the Gulf of Finland (101 days), the Gulf of Riga (111 days) and the West coast of Spitsbergen (61 days). In the Canadian Arctic it is worth mentioning the increase of 62 days in Hudson Strait, 36 days in Hudson and Baffin Bays, and 52 days in Davis St. In almost all straits and sounds of the High Canadian Arctic the increase has been clearly non-linear and we prefer to compare the average LIFS in the periods 1979-1983 and 2002-2006. We quote an increase of 87 days in Lancaster Sound and of 74 days in Coronation Gulf. class="ab'>

  11. Understanding the Amundsen Sea Low

    Science.gov (United States)

    McDonald, Adrian

    2016-04-01

    The Amundsen Sea Low (ASL) is a climatological low pressure system located between 170-300 ° E and 60-75°S and is a key component of the non-zonal climatological circulation at high southern latitudes. With reanalysis output identifying that climatologically the low in the Amundsen Sea is the deepest of three mean sea level pressure (MSLP) centres observed around Antarctica. The ASL strongly modulates West Antarctic climate with impacts on sea ice extent, temperature and precipitation, via its controlling influence on the variability of the meridional wind field. It has also been shown to have a significant influence on the atmospheric circulation in the Ross Sea region and to strongly modulate temperature and moisture advection over the Antarctic Peninsula. Previous work has demonstrated strong relationships between the depth of the ASL and cyclone densities in the region. However, interestingly a recent review identified that it is not easy to relate the storm density and depths of the cyclones to the climatological ASL, since the climatological location of the ASL does not occur at a clear maximum of storm activity. This study examines output from the ERA-interim reanalyses around Antarctica to further understand the contributors to the climatological pattern, partially in an effort to identify whether a more physically meaningful ASL depth index (normally simply defined as the monthly minimum MSLP) can be created. In this effort, storm track data derived from the ERA-Interim reanalysis and mean sea level pressure data bandpass filtered to accentuate synoptic scale variability are first examined. The contribution of persistent positive anomalies in the mean sea level pressure (defined as 8hPa positive anomalies from the climatological mean for a period of 5 days) in the region surrounding the Amundsen sea is also examined to identify whether blocking plays a role. Finally, the frequency of persistent negative anomalies (defined as a negative 8hPa occurring for

  12. Integrating out the Dirac sea

    Energy Technology Data Exchange (ETDEWEB)

    Karbstein, Felix

    2009-07-08

    We introduce a new method for dealing with fermionic quantum field theories amenable to a mean-field-type approximation. In this work we focus on the relativistic Hartree approximation. Our aim is to integrate out the Dirac sea and derive a no-sea effective theory'' with positive energy single particle states only. As the derivation of the no-sea effective theory involves only standard Feynman diagrams, our approach is quite general and not restricted to particular space-time dimensions. We develop and illustrate the approach in the ''large N'' limit of the Gross-Neveu model family in 1+1 dimensions. As the Gross-Neveu model has been intensely studied and several analytical solutions are known for this model, it is an ideal testing ground for our no-sea effective theory approach. The chiral Gross-Neveu model, also referred to as 1+1 dimensional Nambu-Jona-Lasinio model, turns out to be of particular interest. In this case, we explicitly derive a consistent effective theory featuring both elementary ''{pi} meson'' fields and (positive energy) ''quark'' fields, starting from a purely fermionic quantum field theory. In the second part of this work, we apply our approach to the Walecka model in 1+1 and 3+1 dimensions. As the Dirac sea caused considerable difficulties in attempts to base nuclear physics on field theoretic models like the Walecka model, mean-field calculations were typically done without the sea. We confront several of these mean-field theory results with our no-sea effective theory approach. The potential of our approach is twofold. While the no-sea effective theory can be utilized to provide new analytical insights in particular parameter regimes, it also sheds new light on more fundamental issues as the explicit emergence of effective, Dirac-sea induced multi-fermion interactions in an effective theory with positive energy states only. (orig.)

  13. Circumpolar polynya regions and ice production in the Arctic: results from MODIS thermal infrared imagery from 2002/2003 to 2014/2015 with a regional focus on the Laptev Sea

    Science.gov (United States)

    Preußer, Andreas; Heinemann, Günther; Willmes, Sascha; Paul, Stephan

    2016-12-01

    High-resolution MODIS thermal infrared satellite data are used to infer spatial and temporal characteristics of 17 prominent coastal polynya regions over the entire Arctic basin. Thin-ice thickness (TIT) distributions (≤ 20 cm) are calculated from MODIS ice-surface temperatures, combined with ECMWF ERA-Interim atmospheric reanalysis data in an energy balance model for 13 winter seasons (2002/2003 to 2014/2015; November to March). From all available MODIS swath data, daily thin-ice thickness composites are computed in order to derive quantities such as polynya area and total thermodynamic (i.e., potential) ice production. A gap-filling approach is applied to account for cloud and data gaps in the MODIS composites. All polynya regions combined cover an average thin-ice area of 226.6 ± 36.1 × 103 km2 in winter. This allows for an average total winter-accumulated ice production of about 1811 ± 293 km3, whereby the Kara Sea region, the North Water polynya (both 15 %), polynyas on the western side of Novaya Zemlya (20 %), as well as scattered smaller polynyas in the Canadian Arctic Archipelago (all combined 12 %) are the main contributors. Other well-known sites of polynya formation (Laptev Sea, Chukchi Sea) show smaller contributions and range between 2 and 5 %. We notice distinct differences to earlier studies on pan-Arctic polynya characteristics, originating in some part from the use of high-resolution MODIS data, as the capability to resolve small-scale (> 2 km) polynyas and also large leads are increased. Despite the short record of 13 winter seasons, positive trends in ice production are detected for several regions of the eastern Arctic (most significantly in the Laptev Sea region with an increase of 6.8 km3 yr-1) and the North Water polynya, while other polynyas in the western Arctic show a more pronounced variability with varying trends. We emphasize the role of the Laptev Sea polynyas as being a major influence on Transpolar Drift characteristics through

  14. Sea Ice Concentration and Extent

    Science.gov (United States)

    Comiso, Josefino C.

    2014-01-01

    Among the most seasonal and most dynamic parameters on the surface of the Earth is sea ice which at any one time covers about 3-6% of the planet. In the Northern Hemisphere, sea ice grows in extent from about 6 x 10(exp 6) sq km to 16 x 10(exp 6) sq km, while in the Southern Hemisphere, it grows from about 3 x 10(exp 6) sq km to about 19 x 10(exp 6) sq km (Comiso, 2010; Gloersen et al., 1992). Sea ice is up to about 2-3 m thick in the Northern Hemisphere and about 1 m thick in the Southern Hemisphere (Wadhams, 2002), and compared to the average ocean depth of about 3 km, it is a relatively thin, fragile sheet that can break due to waves and winds or melt due to upwelling of warm water. Being constantly advected by winds, waves, and currents, sea ice is very dynamic and usually follows the directions of the many gyres in the polar regions. Despite its vast expanse, the sea ice cover was previously left largely unstudied and it was only in recent years that we have understood its true impact and significance as related to the Earths climate, the oceans, and marine life.

  15. Iodine emissions from the sea ice of the Weddell Sea

    Directory of Open Access Journals (Sweden)

    H. M. Atkinson

    2012-11-01

    Full Text Available Iodine compounds were measured above, below and within the sea ice of the Weddell Sea during a cruise in 2009, to make progress in elucidating the mechanism of local enhancement and volatilisation of iodine. I2 mixing ratios of up to 12.4 pptv were measured 10 m above the sea ice, and up to 31 pptv was observed above surface snow on the nearby Brunt Ice Shelf – large amounts. Atmospheric IO of up to 7 pptv was measured from the ship, and the average sum of HOI and ICl was 1.9 pptv. These measurements confirm the Weddell Sea as an iodine hotspot. Average atmospheric concentrations of CH3I, C2H5I, CH2ICl, 2-C3H7I, CH2IBr and 1-C3H7I were each 0.2 pptv or less. On the Brunt Ice Shelf, enhanced concentrations of CH3I and C2H5I (up to 0.5 and 1 pptv respectively were observed in firn air, with a diurnal profile that suggests the snow may be a source. In the sea ice brine, iodocarbons concentrations were over 10 times those of the sea water below. The sum of iodide + iodate was depleted in sea ice samples, suggesting some missing iodine chemistry. Flux calculations suggest I2 dominates the iodine atom flux to the atmosphere, but models cannot reconcile the observations and suggest either a missing iodine source or other deficiencies in our understanding of iodine chemistry. The observation of new particle formation, consistent with the model predictions, strongly suggests an iodine source. This combined study of iodine compounds is the first of its kind in this unique region of sea ice rich in biology and rich in iodine chemistry.

  16. Iodine emissions from the sea ice of the Weddell Sea

    Directory of Open Access Journals (Sweden)

    H. M. Atkinson

    2012-05-01

    Full Text Available Iodine compounds were measured above, below and within the sea ice of the Weddell Sea during a cruise in 2009, to elucidate the mechanism of local enhancement and volatilisation of iodine. I2 mixing ratios of up to 12.4 pptv were measured 10 m above the sea ice, and up to 31 pptv was observed above surface snow on the nearby Brunt Ice Shelf – large amounts. Atmospheric IO of up to 7 pptv was measured from the ship, and the average sum of HOI and ICl was 1.9 pptv. These measurements confirm the Weddell Sea as an iodine hotspot. Average atmospheric concentrations of CH3I, C2H5I, CH2ICl, 2-C3H7I, CH2IBr and 1-C3H7I were each 0.2 pptv or less. On the Brunt Ice Shelf, enhanced concentrations of CH3I and C2H5I (up to 0.5 and 1 pptv, respectively were observed in firn air, with a diurnal profile that suggests the snow may be a source. In the sea ice brine, iodocarbons concentrations were over 10 times those of the sea water below. The sum of iodide + iodate was depleted in sea ice samples, suggesting some missing iodine chemistry. Flux calculations suggest I2 dominates the iodine atom flux to the atmosphere, but models cannot reconcile the observations and suggest either a missing iodine source or other deficiencies in our understanding of iodine chemistry. The observation of new particle formation, consistent with the model predictions, strongly suggests an iodine source. This combined study of iodine compounds is the first of its kind in this unique region of sea ice rich in biology and rich in iodine chemistry.

  17. Alone by the Sea

    Directory of Open Access Journals (Sweden)

    Zoran Ferić

    2015-06-01

    Full Text Available 1.At first the island is just a sign on a yellow board with a drawing of a vessel and the letters saying “Car Ferry,” then it is a grayish silhouette in the blue of the sea, and then, later still, an acquaintance working on the ferry, who just nods briefly in greeting. Jablanac, ferry port, its pleasant lobby, and then, from the upper deck, a giant rock approaching. That is the object of a year-long desire: the moment of stepping off the boat and smelling the rosemary, diesel and sheep droppings, seeing the sharp rocks looking at the Strait of Senj, coarse limestone in sharp opposition to the signs that say: Benvenuti, Welcome, Willkommen!At home, on the terrace, in the shade of the oleander, there’s no wish to eat. Only swimming trunks are put on and then, barefoot, without a towel or sun-tanning lotion, off to the beach.“Why won’t you eat something?” grandma asks.She knows that there’s an exciting world waiting out there, but she knows nothing of the details. All friends went on a boat trip. And suddenly one step from the shade of a path covered with oleanders and acacias leads into the burning sun of the afternoon. The light screams, just like children in the water, just like white objects that radiate as if there are some powerful light bulbs within. The feeling of freedom of someone who has just arrived in a foreign place and can now do anything. There’s no one familiar on the beach, they all got in the boat and left. The seafront leading to the camp is full of people, naked children with dirty faces licking ice cream, young families pushing strollers, groups of teenagers who have just woken up from their last night’s party. But there’s no one that must be greeted. The feeling of freedom that’s at the same time close to death. Suddenly, all paths are open. That there are no obligations or friends waiting, this afternoon, until they come back, is a complete boon.

  18. On The Black Sea Surozhian

    Science.gov (United States)

    Caraivan, Glicherie; Corneliu, Cerchia

    2016-04-01

    Some Black Sea researchers still support the idea of no other connection to the Mediterranean Sea between LGM and Karangatian Stage (Riss - Wurm). We try to clarify the source of these disagreements. C14 AMS age data (HERAS Project) made on undisturbed samples from a new Mamaia drilling hole where compared with the classical Black Sea stratigraphic schemes. A first transgressive event (Zone D) is found between 38.00 - 20.20 m depth. Zone D4 shows a fairly rapid rise of sea level, about 10 m below the present one indicating an inner shelf marine polyhaline environment. AMS age data show 14C ages between 53690 - 47359 y (MIS 1), corresponding to the "Surozhian Beds" of Popov. The "beach rock" from Zone E marks the decrease of the sea level after the maximum reached in Zone D4. Zone E mollusc shells AMS data, indicate 14C ages of 48724 - 44604 y, suggesting a long-time reworked material from the previous D4 zone sediments, and represents the beginning of the "regressive Tarkankutian" sequence.The Last Glacial Maximum (LGM) led to the retreat of the sea level down to about 100 m below the current one (27-17 ky BP), followed by an retreat of the shoreline to the present position. At the beginning of the Holocene - MIS 1 (8408-8132 cal. y BP), Black Sea brackish water level grew rapidly, up to -14 m below the present one (Zone F: 22, 57-20, 20 m). Zone F deposits could be correlated with the Bugazian strata. Then, a continuous rising of the Black Sea level is recorded up to a maximum of -2 m under the present one, about 6789 - 7063 cal. y BP, when a transgressive spurt ("Neolithic transgression") may have taken place. After that, given a weak Danubian sedimentary input, coastal erosion intensified. The coarse sandy sediments were reworked and pushed over the previous peat deposits, and suggest a classical "sedimentary regression", not a sea-level decrease. During the last 1.5 ky, sea level has risen towards the current one. Previous C14 dates from "Karangatian

  19. GHRSST Level 4 DMI_OI North Sea and Baltic Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

  20. The politics of SEA indicators

    DEFF Research Database (Denmark)

    Gao, Jingjing; Kørnøv, Lone; Christensen, Per

    2013-01-01

    The use of indicators is not only technical and science-led, but also a value-laden social process, and thus concerns public participation, political judgment and decision-making. This article approaches the Chinese SEA indicator system from a science-policy interface and aims at: 1) contributing...... to the general recognition of indicators functioning at science-policy interfaces in SEA, and 2) analysing, through a Chinese case-study, to what extent national guidelines mediate the science-policy interaction. The overall finding is a strong emphasis on technical/science aspects found in the Chinese SEA...... guidance, and a weak explicit recognition that policy plays a role in choosing and using indicators. Recent development, however, indicates a growing recognition of the politics involved and thus also leads to more involvement of stakeholders....

  1. How SEA can inform lenders

    DEFF Research Database (Denmark)

    Banhalmi-Zakar, Zsuzsa; Larsen, Sanne Vammen

    SEA can be a powerful tool to improve decision-making for plans, policies and programmes, but it can also be a useful for banks. SEA can help lenders address the reputational risks they are exposed to through financing projects that may have a negative impact on the environment and it can also help...... with identifying the financial incentives that ‘green’ projects attract. Although bank lending decisions apply to projects, examination of the lending practices of an Australian and a Hungarian bank have shown that decisions about the type of projects to target or avoid are also made at strategic level......, such as in the credit policies. It was also found that in some cases lenders become involved in project planning at a very early stage, when projects are conceptualized, and certainly before formal approval is sought from relevant authorities and an EIA is conducted. This suggests that SEA can be a useful tool...

  2. EXPERIMENTS OF SEA ICE SIMULATION

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-ying; ZHANG Xue-hong; YU Ru-cong; LIU Hai-long; YU Yong-qiang

    2005-01-01

    As a substitute for the original displaced pole grids, a simple rotated spherical coordinate system was introduced into the Community Sea Ice Model version 4(CSIM4), which is a component of the Community Climate System Model(CCSM) of the American National Center of Atmospheric Research(NCAR), to deal with the "pole problems".In the new coordinates, both the geographical North Pole and South Pole lie in the model equator and grid sizes near the polar region are more uniform.With reanalysis dataset of American National Centers for Environment Prediction(NCEP) and Levitus dataset without considering sub-mixed layer heat flux, the model was integrated for 100 years with thermodynamics process involved only in the former 49 years and both dynamic and thermodynamic processes involved in the left time.Inner consistency of model results was checked with no contradiction found.The results of last 10 years' model output were analyzed and it is shown that the simulated sea ice seasonal variation is rational whereas sea ice extent in the Barents Sea in winter is larger than that of observation.Numerical experiment on influence of sub-mixed layer heat flux was also carried out and it is shown that the sub-mixed layer heat flux can modulate seasonal variation of sea ice greatly.As a model component, the sea ice model with rotated spherical coordinates was coupled with other models (the oceanic general circulation model is the LASG/IAP Climate System Ocean Model(LICOM) with reduced grid, other models are components of NCAR CCSM2) forming a climate system model and its preliminary results were also given briefly.

  3. Mapping the deep sea floor

    DEFF Research Database (Denmark)

    Nielsen, Kristian Hvidtfelt

    By the early 20th century, oceanographers intensified their efforts to map the deep sea. The great depth of the Philippine Trench was first observed by the German Planet Expedition in 1912. During World War II, the US naval vessel Cape Johnson used directional echo-sounding to obtain a depth of 10...... Trench in order to map its bathymetric features. The resulting maps are presented in this poster. Unlike many other contemporary developments in deep sea topography and cartography that were shaped by the Cold War, the Galathea maps of the Philippine Trench were intimately connected with the expedition...

  4. Sailing In Sea of Commerce

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The law of big fish swallowing little fish has expired when it comes to the era of new economy.What prevails nowadays in the sea of commerce is quick fish swallowing slow fish.In the Internet economy,small companies are not destined to lose to giants,but slow ones are doomed to become prey of their quick counterparts. The swiftly rising Yongkang Group has made a breakthrough in dental treatment by translating the law into practice.It is called"Law of the Sea."‘Law of the Sea’

  5. Black Sea coastal forecasting system

    Directory of Open Access Journals (Sweden)

    A. I. Kubryakov

    2012-03-01

    Full Text Available The Black Sea coastal nowcasting and forecasting system was built within the framework of EU FP6 ECOOP (European COastalshelf sea OPerational observing and forecasting system project for five regions: the south-western basin along the coasts of Bulgaria and Turkey, the north-western shelf along the Romanian and Ukrainian coasts, coastal zone around of the Crimea peninsula, the north-eastern Russian coastal zone and the coastal zone of Georgia. The system operates in the real-time mode during the ECOOP project and afterwards. The forecasts include temperature, salinity and current velocity fields. Ecosystem model operates in the off-line mode near the Crimea coast.

  6. Sea-State Engineering Analysis System (SEAS). Revision.

    Science.gov (United States)

    1986-11-01

    New revised editions/supplements will be issued as other new data sets or capabilities are added to SEAS. 20 ,S’Rl9U’ ON, AVAILABILTY OF ABSTRACT 121...system resource usage prints). 9.2.3 Disconnect the telephone receiver from the terminal. 9.2.4 Turn the terminal power switch to the "OFF" position. kt

  7. Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19 by multiple Soviet Union institutes (NODC Accession 0077413)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19...

  8. Implementing the European SEA Directive in planning

    DEFF Research Database (Denmark)

    Kørnøv, Lone

    The paper describes how the European SEA Directive can complement the existing planning practice in Denmark.......The paper describes how the European SEA Directive can complement the existing planning practice in Denmark....

  9. Quarterly Fishery Surveys - Salton Sea [ds428

    Data.gov (United States)

    California Department of Resources — In the spring of 2003, California Department of Fish and Game (CDFG) personnel began quarterly sampling of Salton Sea fish at fourteen stations around the sea, as...

  10. Range Extent for southern sea otters 2016

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The GIS shapefile "Range extent of southern sea otters 2016" is a simple polyline representing the geographic distribution of the southern sea otter (Enhydra lutris...

  11. Erective Sea Embankment with PCC Piles

    Institute of Scientific and Technical Information of China (English)

    LIU Han-long; FEI Kang; DENG An; ZHANG Ting

    2005-01-01

    The sea embankment is a critical civil works in marine and coastal engineering. In this study, an innovative technique is proposed for constructing erective sea embankments. In the construction of sea embankments, this technique integrates PCC pile installation, PVDs drainage systems, and geotextile reinforcements, resulting in sea embankments with PCC piles. In the application of a sea embankment with PCC piles, PCC piles are employed as the retaining structures;the soft sea ground inside PCC piles is drained and improved by PVDs and vacuum-surcharge combined preloading; geotextile-reinforced backfills lying over the improved soft ground form the embankment body. Brief descrptions of the fundamentals, design and construction of the sea embankment with PCC piles are presented. A case study on the stability of sea embankment with PCC piles is presented as well.

  12. 2010 USGS Lidar: Salton Sea (CA)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The USGS Salton Sea project encompasses a 5-kilometer buffer around the Salton Sea, California. Dewberry classified LiDAR for a project boundary that touches 623...

  13. Sea turtles sightings in North Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea turtles sightings are reported to the NMFS Beaufort Laboratory sea turtle program by the general public as they are fishing, boating, etc. These sightings...

  14. Extended Reconstructed Sea Surface Temperature (ERSST)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature analysis derived from the International Comprehensive...

  15. Generation and evolution of Cenozoic alkaline rocks from the Chukchi peninsula, Russia: Insight from melt and fluid inclusions%俄罗斯Chukchi半岛新生代碱性岩的形成和演化:熔体和流体包裹体证据

    Institute of Scientific and Technical Information of China (English)

    Irina P.Solovova; Theodoros Ntaflos; Andrei Girnis; Natalya N.Kononkova; Vyacheslav V.Akinin

    2007-01-01

    Melt and fluid inclusions were studied in the minerals of Cenozoic olivine melanephelinites from the Chukchi Peninsula, Russia. The rock contain several generations of olivine phenocrysts varying in composition at mg= 0.88 ~ 0.77. The phenocrysts bear fluid and melt inclusions recording various stages of melt crystallization in volcanic conduits and shallow magma chambers. Primary fluid inclusions are CO2-dominated with a density of up to 0.93 g/cm3. All fluid inclusions are partially leaked, which is indicated by haloes of tiny fluid bubbles around large fluid inclusions in minerals. Melt inclusions contain various daughter crystals, which were completely resorbed in thermometric experiments at about 1230℃. Assuming that this temperature corresponds to the entrapment conditions of the CO2 fluid inclusions, the minimum pressure of the beginning of magma degassing is estimated as 800MPa. Variations in the compositions of homogenized silicate melt inclusions indicate that olivine was the earliest crystalline phase followed by clinopyroxene, nepheline and orthoclase. This sequence is in agreement with the mineralogy of the rocks. The melts are strongly enriched in incompatible trace elements and volatiles (in addition to CO2, high Cl, F, and S contents were detected). There are some differences between the compositions of melts trapped in minerals from different samples. Variations in SiO2, FeO, and incompatible element contents are probably related to melt generations at various levels in a homogeneous mantle reservoir.

  16. Estimating sea floor dynamics in the Southern North Sea to improve bathymetric survey planning

    NARCIS (Netherlands)

    Dorst, Leendert Louis

    2009-01-01

    Safe nautical charts require a carefully designed bathymetric survey policy, especially in shallow sandy seas that potentially have dynamic sea floor patterns. Bathymetric resurveying at sea is a costly process with limited resources, though. A pattern on the sea floor known as tidal sand waves is c

  17. 50 CFR 697.12 - At-sea sea sampler/observer coverage.

    Science.gov (United States)

    2010-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) ATLANTIC COASTAL FISHERIES COOPERATIVE... must: (1) Notify the sea sampler/observer of any sea turtles, marine mammals, or other specimens taken by the vessel. (2) Provide the sea sampler/observer with sea turtles, marine mammals, or...

  18. Multiscale Models of Melting Arctic Sea Ice

    Science.gov (United States)

    2014-09-30

    1 Multiscale Models of Melting Arctic Sea Ice Kenneth M. Golden University of Utah, Department of Mathematics phone: (801) 581-6851...feedback has played a major role in the recent declines of the summer Arctic sea ice pack. However, understanding the evolution of melt ponds and sea...Models of Melting Arctic Sea Ice 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER

  19. [Multiple scattering of visible and infrared light by sea fog over wind driving rough sea surface].

    Science.gov (United States)

    Sun, Xian-Ming; Wang, Hai-Hua; Lei, Cheng-Xin; Shen, Jin

    2013-08-01

    The present paper is concerned with computing the multiple scattering characteristics of a sea fog-sea surface couple system within this context. The single scattering characteristics of sea fog were studied by Mie theory, and the multiple scattering of sunlight by single sea fog layer was studied by radiative transfer theory. The reflection function of a statistically rough ocean surface was obtained using the standard Kirchhoff formulation, with shadowing effects taken into account. The reflection properties of the combined sea fog and ocean surface were obtained employing the adding method, and the results indicated that the reflected light intensity of sea fog increased with the sea background.

  20. India and the South China Sea Dispute

    Institute of Scientific and Technical Information of China (English)

    Ma Jiali

    2012-01-01

    South China Sea is a sea area of great significance. It lies between the Pacific and Indian Oceans, a crucial waterway bridging East Asia, Southeast Asia and South Asia. In general, South China Sea is a rich deposit of oil and fishing resources, a transportation hub of strategic importance, and an important buffer zone to safeguard China's maritime rights and interests.

  1. 33 CFR 2.22 - Territorial sea.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Territorial sea. 2.22 Section 2... Jurisdictional Terms § 2.22 Territorial sea. (a) With respect to the United States, the following apply— (1) Territorial sea means the waters, 12 nautical miles wide, adjacent to the coast of the United States...

  2. Parasites in the Wadden Sea food web

    NARCIS (Netherlands)

    Thieltges, D.W.; Engelsma, M.Y.; Wendling, C.C.; Wegner, M.

    2013-01-01

    While the free-living fauna of the Wadden Sea has received much interest, little is known on the distribution and effects of parasites in the Wadden Sea food web. However, recent studies on this special type of trophic interaction indicate a high diversity of parasites in the Wadden Sea and suggest

  3. 50 CFR 223.205 - Sea turtles.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Sea turtles. 223.205 Section 223.205... Threatened Marine and Anadromous Species § 223.205 Sea turtles. (a) The prohibitions of section 9 of the Act (16 U.S.C. 1538) relating to endangered species apply to threatened species of sea turtle, except...

  4. OW NASA SeaWIFS Ocean Color

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains satellite-derived sea-surface ocean color (chlorophyll-a) measurements collected by means of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS)...

  5. Generic Hurricane Extreme Seas State

    DEFF Research Database (Denmark)

    Wehmeyer, Christof; Skourup, Jesper; Frigaard, Peter

    2012-01-01

    the US east coast and the Gulf of Mexico (1851 - 2009) and Japanese east coast (1951 -2009) form the basis for Weibull extreme value analyses to determine return period respective maximum wind speeds. Unidirectional generic sea state spectra are obtained by application of the empirical models...

  6. The Sea Ice Board Game

    Science.gov (United States)

    Bertram, Kathryn Berry

    2008-01-01

    The National Science Foundation-funded Arctic Climate Modeling Program (ACMP) provides "curriculum resource-based professional development" materials that combine current science information with practical classroom instruction embedded with "best practice" techniques for teaching science to diverse students. The Sea Ice Board…

  7. Radar for Mapping Sea Ice

    Science.gov (United States)

    Barath, F. T.; Jordan, R. L.

    1983-01-01

    X-band system has 100-m2 resolution. Wide swath imaging radar of synthetic aperature type transmits signal to ground station for subsequent processing into imagery. Concept meets functional requirements for continuously mapping sea ice in north and south polar regions.

  8. Killer storms from the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    The author has discussed the distruction taking place due to cyclone in the Indian subcontinent of formation which is said to be the result of thermal fronts in the atmosphere and sea interaction of different air masses is discussed in detailed...

  9. IAHR List of Sea Parameters

    DEFF Research Database (Denmark)

    Frigaard, Peter; Helm-Petersen, J; Klopman, G.

    1997-01-01

    A Working Group on multidirectional waves formed by the International Association for Hydraulic Research has proposed an update of the IAHR List of Sea State Parameters from 1986 in the part concerning directional. Especially wave structure interaction with reflection of the waves have been treated....

  10. Chicken Porridge with Sea Cucumber

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Main ingredients: 50 grams of chicken breast, 200 grams of gray sea cucumbers Supplementary ingredients: 100 grams of water chestnut, the whites of four eggs, MSG, salt, wine, meat soup, starch, sugar, scallions, ginger, soy sauce Directions: Chop up the chicken breast and water chestnut into small

  11. Past and present Aral Sea

    Science.gov (United States)

    Dukhovniy, Viktor; Stulina, Galina; Eshchanov, Odylbek

    2013-04-01

    The tragedy of disappearing of Aral Sea is well known to the World. Before and after collapse of Soviet Union, a huge quantity of scientific and popular editions described with grief the situation around the Aral Sea. After the NIS states became independent, World Bank, UNDP, UNEP in proper competition with each other had provided some assessment of the situation through presentation of some small and medium grants, but after 2000, the local population remained alone with own problems. Although on the eyes of the present generation a unique transformation of great water body into deserts took place, the global scientific community did not find forces and financing for real and detail investigation of the processes accompanying the Sea shrinking and land formation. We should acknowledge and give big respect to NATO, later to German Government that through GTZ (now GIZ) - German International Collaboration Agency - and GFZ (Potzdam) paid attention to this area of environment crisis and organized scientific and protective design in the so-called Priaralie - the territory around the drying Sea and delta of the two rivers - Amudarya and Syrdarya. Thank to this assistance, the local specialists in collaboration with limited a number of foreign scientists (N.Aladin, P.Zavialov, Joop de Schutter, Hans Wilps, Hedi Oberhansli) organized significant works for detail socioeconomic, ecological and hydrological assessment situation in Priaralie and on the Aral sea coast. On this base, Ministry of Agriculture and Water resources of Uzbekistan and State Committee of Water resources of Kazakhstan developed a plan of rehabilitation of Amudarya and Syrdarya deltas and started implementation of these projects. If Kazakh water authority moved ahead in wetland restoration faster, a forestation of delta and drying bed of Aral Sea got big success in Uzbek territory. 244 thousands hectares of saxsaul and tamarix were planted for protection of the Priaralie. By request of GTZ SIC, ICWC

  12. Salton Sea Ecosystem Monitoring Project

    Science.gov (United States)

    Miles, A. Keith; Ricca, Mark A.; Meckstroth, Anne; Spring, Sarah E.

    2009-01-01

    The Salton Sea is critically important for wintering and breeding waterbirds, but faces an uncertain future due to water delivery reductions imposed by the Interstate and Federal Quantification Settlement Agreement of 2003. The current preferred alternative for wetland restoration at the Salton Sea is saline habitat impoundments created to mitigate the anticipated loss of wetland habitat. In 2006, a 50-hectare experimental complex that consisted of four inter-connected, shallow water saline habitat ponds (SHP) was constructed at the southeastern shoreline of the Salton Sea and flooded with blended waters from the Alamo River and Salton Sea. The present study evaluated ecological risks and benefits of the SHP concept prior to widespread restoration actions. This study was designed to evaluate (1) baseline chemical, nutrient, and contaminant measures from physical and biological constituents, (2) aquatic invertebrate community structure and colonization patterns, and (3) productivity of and contaminant risks to nesting waterbirds at the SHP. These factors were evaluated and compared with those of nearby waterbird habitat, that is, reference sites.

  13. Climate change challenges for SEA

    DEFF Research Database (Denmark)

    Larsen, Sanne Vammen

    This paper takes a theoretical perspective on the challenges that climate changes pose for SEA. The theoretical framework used is the sociologist Ulrich Beck’s theory of risk society and the aspects that characterise this society. Climate change is viewed as a risk, and the theory is used to derive...

  14. Facing up to sea rise.

    Science.gov (United States)

    Pernetta, J

    1994-01-01

    A milder and less extreme climate, abundance of fish and mollusks, transport and communication, and fertile land at low altitudes have drawn humans to coastal areas and river valleys for centuries. More than 60% of the world's population occupy the 150 km closest to the coast. Millions of tourists come to coastlines and small tropical islands for recreation. About 80% of the global fish supply originates from the 19 km closest to the shore. Fish are the only protein source for the rapidly growing populations in many developing countries. Global climate change is increasing the sea level so much that by 2050, the mean increase will be about 38 cm (24-52 cm). The Intergovernmental Panel on Climate Change (IPCC) notes that the effects of sea level rise will differ from place to place. Direct effects are flooding of low-lying coastal areas and increased erosion rates. An indirect effect includes higher water tables and intrusion of saline water into aquifers, resulting in loss of fresh ground water resources. These effects may make coastal areas less suitable for settlement and agriculture. Coral sand settled on top of coral reefs makes up the unstable, small atoll islands of the Pacific and Indian Oceans. People on these islands depend almost entirely on the sea for their livelihood and on the small amount of fresh water with which they grow root crops and drink. Rising sea levels also threaten low lying countries, e.g., Bangladesh, and densely populated deltas, e.g., the Nile. Changes in the frequency and severity of flooding will increase Bangladesh's dependence on foreign aid. IPCC sees 3 possible responses to the rising sea level: defense, retreat, and accommodation. Accommodation is the only practical choice for many developing countries. A switch from rice cultivation to mariculture of prawns and fish is an example of accommodation. We need to more completely understand the natural processes in coastal environments to be better prepared for climate change.

  15. Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian Sea and White Sea from R/Vs Artemovsk, Atlantida, Okeanograf, Professor Rudovits, and ice observations, 1957 - 1995 (NODC Accession 0073674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian...

  16. Jet formation at the sea ice edge

    Science.gov (United States)

    Feltham, D. L.; Heorton, H. D.

    2014-12-01

    The sea ice edge presents a region of many feedback processes between the atmosphere, ocean and sea ice, which are inadequately represented in current climate models. Here we focus on on-ice atmospheric and oceanic flows at the sea ice edge. Mesoscale jet formation due to the Coriolis effect is well understood over sharp changes in surface roughness such as coastlines. This sharp change in surface roughness is experienced by the atmosphere flowing over, and ocean flowing under, a compacted sea ice edge. We have studied a dynamic sea ice edge responding to atmospheric and oceanic jet formation. The shape and strength of atmospheric and oceanic jets during on-ice flows is calculated from existing studies of the sea ice edge and prescribed to idealised models of the sea ice edge. An idealised analytical model of sea ice drift is developed and compared to a sea ice climate model (the CICE model) run on an idealised domain. The response of the CICE model to jet formation is tested at various resolutions. We find that the formation of atmospheric jets during on-ice winds at the sea ice edge increases the wind speed parallel to the sea ice edge and results in the formation of a sea ice edge jet. The modelled sea ice edge jet is in agreement with an observed jet although more observations are needed for validation. The increase in ice drift speed is dependent upon the angle between the ice edge and wind and can result in a 40% increase in ice transport along the sea ice edge. The possibility of oceanic jet formation during on-ice currents and the resultant effect upon the sea ice edge is less conclusive. Observations and climate model data of the polar oceans has been analysed to show areas of likely atmospheric jet formation, with the Fram Strait being of particular interest.

  17. Ecological consequences of sea-ice decline.

    Science.gov (United States)

    Post, Eric; Bhatt, Uma S; Bitz, Cecilia M; Brodie, Jedediah F; Fulton, Tara L; Hebblewhite, Mark; Kerby, Jeffrey; Kutz, Susan J; Stirling, Ian; Walker, Donald A

    2013-08-02

    After a decade with nine of the lowest arctic sea-ice minima on record, including the historically low minimum in 2012, we synthesize recent developments in the study of ecological responses to sea-ice decline. Sea-ice loss emerges as an important driver of marine and terrestrial ecological dynamics, influencing productivity, species interactions, population mixing, gene flow, and pathogen and disease transmission. Major challenges in the near future include assigning clearer attribution to sea ice as a primary driver of such dynamics, especially in terrestrial systems, and addressing pressures arising from human use of arctic coastal and near-shore areas as sea ice diminishes.

  18. Global Warming and Caspian Sea Level Fluctuations

    CERN Document Server

    Ardakanian, Reza

    2013-01-01

    Coastal regions have a high social, economical and environmental importance. Due to this importance the sea level fluctuations can have many bad consequences. In this research the correlation between the increasing trend of temperature in coastal stations due to Global Warming and the Caspian Sea level has been established. The Caspian Sea level data has been received from the Jason-1 satellite. It was resulted that the monthly correlation between the temperature and sea level is high and also positive and almost the same for all the stations. But the yearly correlation was negative. It means that the sea level has decreased by the increase in temperature.

  19. On the Sea, From the Sea, Of the Sea: The Physics of maritime Governance

    Science.gov (United States)

    James, Royce; Page, Eric

    2014-03-01

    The United States Coast Guard Academy Physics Section is proud to present our initial conceptions of ``On the Sea, From the Sea, Of the Sea: The Physics of Maritime Governance,'' a program funded by an APS Outreach Grant in 2013. In our classes, the Physics Section has focused on active student engagement for the past ten years. Recently, we have refined our program to make heavy use of Interactive Lecture Demonstrations (ILDs) and our own highly interactive adaptation which we call Interactive Lecture Labs (ILLs). ``On the Sea'' is a unique opportunity to investigate their use in a different learning modality from our standard college level military academic use. Multigenerational science, technology, engineering, and mathematics (STEM) projects are a prolific source of academic discourse, while learning through play has been touted as an effective learning tool. We plan to investigate group and individual participation, intragroup communication, demographics, and prior skill (or education) in comparison to outcomes in learning objectives through projects designed to educate the Coast Guard Academy and surrounding community on the physics of the Coast Guard's missions. Progress on the lab and demonstration designs, community participation, and our emerging ILL and ILD pedagogical methods, will be reported.

  20. Sea ice thickness and recent Arctic warming

    Science.gov (United States)

    Lang, Andreas; Yang, Shuting; Kaas, Eigil

    2017-01-01

    The climatic impact of increased Arctic sea ice loss has received growing attention in the last years. However, little focus has been set on the role of sea ice thickness, although it strongly determines surface heat fluxes. Here ensembles of simulations using the EC-Earth atmospheric model (Integrated Forecast System) are performed and analyzed to quantify the atmospheric impacts of Arctic sea ice thickness change since 1982 as revealed by the sea ice model assimilation Global Ice-Ocean Modeling and Assimilation System. Results show that the recent sea ice thinning has significantly affected the Arctic climate, while remote atmospheric responses are less pronounced owing to a high internal atmospheric variability. Locally, the sea ice thinning results in enhancement of near-surface warming of about 1°C per decade in winter, which is most pronounced over marginal sea ice areas with thin ice. This leads to an increase of the Arctic amplification factor by 37%.

  1. Episodic sea-floor spreading in the Southern Red Sea

    Science.gov (United States)

    Almalki, Khalid A.; Betts, Peter G.; Ailleres, Laurent

    2014-03-01

    The Red Sea represents the most spectacular example of a juvenile ocean basin on the modern Earth. Synthesis of regional aeromagnetic data, gravity data, seismic refraction data coupled with structural mapping from the Farasan Islands suggest that the opening of the Red Sea is complex and episodic. Modeling of magnetic and gravity data constrained by seismic refraction data reveals the Arabian Shelf is underlain by oceanic and transitional crust and that mafic diking and intrusions are focused at the continental-transitional crust boundary. This relationship is interpreted to indicate that early Miocene diking along the Arabian Escarpment heralded termination of oceanic basin formation and a shift in the locus of extension focused from a central mid-ocean ridge spreading center to the continental-transitional crust zone. Uplift along the Arabian Escarpment caused erosion and Middle to Late Miocene sedimentation of the Farasan Bank onto existing oceanic crust, suggesting that the extensive sedimentary banks of the southern Red Sea are not passive margins. Re-initiation of spreading occurred at ca 5 Ma. Pliocene to Pleistocene Shelf reef systems (Farasan Islands), developed on the flanks of the spreading ridge, are extensively overprinted by normal faults, suggesting that not all crustal extension is accommodated by active spreading.

  2. Variability and Trends in Sea Ice Extent and Ice Production in the Ross Sea

    Science.gov (United States)

    Comiso, Josefino; Kwok, Ronald; Martin, Seelye; Gordon, Arnold L.

    2011-01-01

    Salt release during sea ice formation in the Ross Sea coastal regions is regarded as a primary forcing for the regional generation of Antarctic Bottom Water. Passive microwave data from November 1978 through 2008 are used to examine the detailed seasonal and interannual characteristics of the sea ice cover of the Ross Sea and the adjacent Bellingshausen and Amundsen seas. For this period the sea ice extent in the Ross Sea shows the greatest increase of all the Antarctic seas. Variability in the ice cover in these regions is linked to changes in the Southern Annular Mode and secondarily to the Antarctic Circumpolar Wave. Over the Ross Sea shelf, analysis of sea ice drift data from 1992 to 2008 yields a positive rate of increase in the net ice export of about 30,000 sq km/yr. For a characteristic ice thickness of 0.6 m, this yields a volume transport of about 20 cu km/yr, which is almost identical, within error bars, to our estimate of the trend in ice production. The increase in brine rejection in the Ross Shelf Polynya associated with the estimated increase with the ice production, however, is not consistent with the reported Ross Sea salinity decrease. The locally generated sea ice enhancement of Ross Sea salinity may be offset by an increase of relatively low salinity of the water advected into the region from the Amundsen Sea, a consequence of increased precipitation and regional glacial ice melt.

  3. Relationship between Hadley circulation and sea ice extent in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    ZHOU BoTao; WANG HuiJun

    2008-01-01

    The linkage between Hadley circulation (HC) and sea ice extent in the Bering Sea during March-April is investigated through an analysis of observed data in this research. It is found that HC is negatively correlated to the sea ice extent in the Bering Sea, namely, strong (weak) HC is corresponding to less (more) sea ice in the Bering Sea. The present study also addresses the large-scale atmospheric general circulation changes underlying the relationship between HC and sea ice in the Bering Sea. It follows that a positive phase of HC corresponds to westward located Aleutian low, anomalous southerlies over the eastern North Pacific and higher temperature in the Bering Sea, providing unfavorable atmospheric and thermal conditions for the sea ice forming, and thus sea ice extent in the Bering Sea is decreased, and vice versa. In addition, it is further identified that East Asian-North Pacific-North America telecon-nection may play an important role in linking HC and changes of atmospheric circulations as well as sea ice in the Bering Sea.

  4. Micromechanics of Sea Urchin spines.

    Directory of Open Access Journals (Sweden)

    Naomi Tsafnat

    Full Text Available The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine's unique porous structure, based on micro-computed tomography (microCT and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine's architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material.

  5. Mind the gap in SEA

    DEFF Research Database (Denmark)

    Larsen, Sanne Vammen; Kørnøv, Lone; Wejs, Anja

    2012-01-01

    and discussed, mainly based on Scott's theory of institutions. The institutional analysis highlights a regulatory element, since the assessment of climate change synergies is underpinned by legislation, but not by guidance. This means that great focus is on normative elements such as the local interpretation...... of legislation and of climate change mitigation and adaptation. The analysis also focuses on how the fragmentation of the organisation in which climate change and SEA are embedded has bearings on both normative and cultural–cognitive elements. This makes the assessment of synergies challenging. The evidence......This article takes its point of departure in two approaches to integrating climate change into Strategic Environmental Assessment (SEA): Mitigation and adaptation, and in the fact that these, as well as the synergies between them and other policy areas, are needed as part of an integrated...

  6. Sea Power. Quickscan; Zeekracht. Quickscan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-08-15

    The Dutch Stichting Natuur en Milieu (The Netherlands Foundation for Nature and Environment - SNM) takes the view that the long time span between application for a permit and the realization of offshore wind parks in the North Sea is the result of unnecessary bureaucracy. Therefore SNM has asked the Kafka Brigade to list the procedures for construction of offshore wind parks in the North Sea that might be causing these delays. [mk]. [Dutch] de Stichting Natuur en Milieu (SNM) is van mening dat de oorzaak van de lange doorlooptijd die ligt tussen het aanvragen van een vergunning en de realisatie van offshore windparken in de Noordzee ligt in de onnodige bureaucratie. SNM heeft daarom de Kafkabrigade gevraagd een inventarisatie te maken van procedures rond het bouwen van offshore windmolenparken in de Noordzee die mogelijk vertragend kunnen werken.

  7. Open Ocean Bilging, Arabian Sea

    Science.gov (United States)

    1989-01-01

    These dual oil slicks on the ocean surface are the result of tanker ships flushing their tanks (bilging) in the Arabian Sea (18.5N, 62.5E). These two ships flushed out their bilges, apparently contaminated with bunker oil, leaving oily residues on the ocean's surface. One wake, believed to have been done earlier than the other, has been broadened by the effects of surface winds and current.

  8. Coastal and Semi Enclosed Seas

    Science.gov (United States)

    2016-06-07

    Numerical model process and sensitivity studies are conducted to better understand the dynamics and thermodynamics of shallow and deep semi-enclosed seas...included figures of model results in this report, output from these forecasts are now publicly available through the NRL website listed under the title of...this document and we would urge researchers with an interest in this system to visit this website . The EAS model will be run longer during the next

  9. Chicken Porridge with Sea Cucumber

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Chicken Porridge with Sea Cucumber is a dish created according to a well-known story about Jia Chang, who raised cocks during the Tang Dynasty. Cockfighting was popular among commonfolk during the Tang Dynasty. Emperor Xuanzong selected 5,000 cocks in Chang’an, and 500 children to feed them and train them to fight. Jia Chang was one of the children. Sent to the

  10. Chemical munitions dumped at sea

    Science.gov (United States)

    Edwards, Margo; Bełdowski, Jacek

    2016-06-01

    Modern chemical warfare is a byproduct of the industrial revolution, which created factories capable of rapidly producing artillery shells that could be filled with toxic chemicals such as chlorine, phosgene and mustard agent. The trench warfare of World War I inaugurated extensive deployments of modern chemical weapons in 1915. Concomitantly, the need arose to dispose of damaged, captured or excess chemical munitions and their constituents. Whereas today chemical warfare agents (CWA) are destroyed via chemical neutralization processes or high-temperature incineration in tandem with environmental monitoring, in the early to middle 20th century the options for CWA disposal were limited to open-air burning, burial and disposal at sea. The latter option was identified as the least likely of the three to impact mankind, and sea dumping of chemical munitions commenced. Eventually, the potential impacts of sea dumping human waste were recognized, and in 1972 an international treaty, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, was developed to protect the marine environment from pollution caused by the dumping of wastes and other matter into the ocean. By the time this treaty, referred to as the London Convention, was signed by a majority of nations, millions of tons of munitions were known to have been disposed throughout the world's oceans.

  11. Fracture Networks in Sea Ice

    Directory of Open Access Journals (Sweden)

    Jonas Nesland Vevatne

    2014-04-01

    Full Text Available Fracturing and refreezing of sea ice in the Kara sea are investigated using complex networkanalysis. By going to the dual network, where the fractures are nodes and their intersectionslinks, we gain access to topological features which are easy to measure and hence comparewith modeled networks. Resulting network reveal statistical properties of the fracturing process.The dual networks have a broad degree distribution, with a scale-free tail, high clusteringand efficiency. The degree-degree correlation profile shows disassortative behavior, indicatingpreferential growth. This implies that long, dominating fractures appear earlier than shorterfractures, and that the short fractures which are created later tend to connect to the longfractures.The knowledge of the fracturing process is used to construct growing fracture network (GFNmodel which provides insight into the generation of fracture networks. The GFN model isprimarily based on the observation that fractures in sea ice are likely to end when hitting existingfractures. Based on an investigation of which fractures survive over time, a simple model forrefreezing is also added to the GFN model, and the model is analyzed and compared to the realnetworks.

  12. Distributions of dimethylsulfide in the Bohai Sea and Yellow Sea of China

    Institute of Scientific and Technical Information of China (English)

    HU Min; TANG Xiao-yan; LI Jin-long; MA Qi-ju

    2003-01-01

    Dimethylsulfide(DMS) measurements in the surface seawater of China eastern coastline were conducted during March 9-10, 1993 in Bohai Sea along the cruise from Dalian to Tianjin and during September 24-25, 1994 in Yellow Sea along the cruise from Shanghai to Qingdao. On the cruise in Bohai Sea DMS concentrations varied from 0. 11 to 2.63 nmol/L with an average of 1.31 nmol/L, while DMS flux Bohai Sea. DMS concentrations and fluxes had a similar spatial trend both in Bohai Sea and Yellow Sea with the correlation coefficients of 0.75 and 0.64, respectively.

  13. Sea-level variation/change and thermal contribution in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    ZUO Juncheng; ZHANG Jianli; DU Ling; LI Peiliang; LI Lei

    2005-01-01

    The long-term sea-level trend in the Bering Sea is obtained by the analysis of TOPEX/Poseidon altimeter data, including the data of two tide gauges. The averaged sea-level in the Bering Sea rises at a rate of 2.47 mm/a from 1992 to 2002. The mean sea-level is falling in the most part of the Bering Sea, especially in its central basin, and it is rising in the northeastern part of the Bering Sea. During the 1998/99 change, the sea-level anomaly differences exhibit a significant sea-level anomaly fall in the deep basin of the Bering Sea,which is roughly in the same position where a prominent SST fall exists. The maximal fall of sea-level is about 10 cm in the southwestern part of the Bering Sea, and the maximal fall of about 2℃ in the SST also appeared in the same region as the sea level did.The steric sea-level change due to temperature variations is discussed. The results are compared with the TOPEX/Poseidon altimeter data at the different spatial scales. It is indicated that the seasonal amplitude of the steric height is about 35% of the observed TOPEX/Poseidon amplitude, which is much smaller than the 83% in the mid-latitudes area. The systematic difference between the TOPEX/Poseidon data with the range of about 7.5 cm and the thermal contribution with the range of about 2.5 cm is about 5 cm. This indicates that the thermal effect on the sea level is not as important as the case in the mid-latitudes area. In the Bering Sea, the phase of the steric height leads the observed sea level by about three months.

  14. The Suspended Sediment Concentration Distribution in the Bohai Sea, Yellow Sea and East China Sea

    Institute of Scientific and Technical Information of China (English)

    BIAN Changwei; JIANG Wensheng; Richard J.Greatbatch; DING Hui

    2013-01-01

    The distribution of the suspended sediment eoncentration (SSC) in the Bohai Sea,Yellow Sea and East China Sea (BYECS) is studied based on the observed turbidity data and model simulation results.The observed turbidity results show that (i)the highest SSC is found in the coastal areas while in the outer shelf sea areas turbid water is much more difficult to observe,(ii) the surface layer SSC is much lower than the bottom layer SSC and (iii) the winter SSC is higher than the summer SSC.The Regional Ocean Modeling System (ROMS) is used to simulate the SSC distribution in the BYECS.A comparison between the modeled SSC and the observed SSC in the BYECS shows that the modeled SSC can reproduce the principal features of the SSC distribution in the BYECS.The dynamic mechanisms of the sediment erosion and transport processes are studied based on the modeled results.The horizontal distribution of the SSC in the BYECS is mainly determined by the current-wave induced bottom stress and the fine-grain sediment distribution.The current-induced bottom stress is much higher than the wave-induced bottom stress,which means the tidal currents play a more significant role in the sediment resuspension than the wind waves.The vertical mixing strength is studied based on the mixed layer depth and the turbulent kinetic energy distribution in the BYECS.The strong winter time vertical mixing,which is mainly caused by the strong wind stress and surface cooling,leads to high surface layer SSC in winter.High surface layer SSC in summer is restricted in the coastal areas.

  15. [Distribution and air-sea fluxes of methane in the Yellow Sea and the East China Sea in the spring].

    Science.gov (United States)

    Cao, Xing-Peng; Zhang, Gui-Ling; Ma, Xiao; Zhang, Guo-Ling; Liu, Su-Mei

    2013-07-01

    A survey was carried out in the Yellow Sea and the East China Sea from March 17 to April 06 of 2011. Dissolved CH4 in various depths were measured and sea-to-air fluxes were estimated. Methane concentrations in surface and bottom waters ranged between 2.39-29.67 nmol x L(-1) and 2.63-30.63 nmol x L(-1), respectively. Methane concentrations in bottom waters were slightly higher than those in surface waters, suggesting the existence of methane source in bottom waters or sediments. The horizontal distribution of dissolved CH4 showed a decrease from the river mouth to the open sea, and was influenced by the freshwater discharge and the Kuroshio intrusion. Surface methane saturations ranged from 93%-1 038%. Sea to air CH4 fluxes were (2.85 +/- 5.11) micromol x (m2 x d)(-1) (5.18 +/- 9.99) micromol x (m2 x d)(-1) respectively, calculated using the Liss and Merlivat (LM86), the Wanninkhof (W92) relationships and in situ wind speeds, and estimated emission rates of methane from the East China Sea and the Yellow Sea range from 7.05 x 10(-2) - 12.0 x 10(-2) Tg x a(-1) and 1.17 x 10(-2) - 2.20 x 10(-2) Tg x a(-1), respectively. The Yellow Sea and East China Sea are the net sources of atmospheric methane in the spring.

  16. Microplastic pollution in deep-sea sediments.

    Science.gov (United States)

    Van Cauwenberghe, Lisbeth; Vanreusel, Ann; Mees, Jan; Janssen, Colin R

    2013-11-01

    Microplastics are small plastic particles (microplastics have been accumulating in the marine environment for decades and have been detected throughout the water column and in sublittoral and beach sediments worldwide. However, up to now, it has never been established whether microplastic presence in sediments is limited to accumulation hot spots such as the continental shelf, or whether they are also present in deep-sea sediments. Here we show, for the first time ever, that microplastics have indeed reached the most remote of marine environments: the deep sea. We found plastic particles sized in the micrometre range in deep-sea sediments collected at four locations representing different deep-sea habitats ranging in depth from 1100 to 5000 m. Our results demonstrate that microplastic pollution has spread throughout the world's seas and oceans, into the remote and largely unknown deep sea.

  17. Sea ice, climate, and multiscale composites

    Science.gov (United States)

    Golden, Kenneth

    2014-03-01

    In September of 2012, the area of the Arctic Ocean covered by sea ice reached its lowest level ever recorded in more than three decades of satellite measurements. In fact, compared to the 1980's and 1990's, this represents a loss of more than half of the summer Arctic sea ice pack. While global climate models generally predict sea ice declines over the 21st century, the precipitous losses observed so far have significantly outpaced most projections. I will discuss how mathematical models of composite materials and statistical physics are being used to study key sea ice processes and advance how sea ice is represented in climate models. This work is helping to improve projections of the fate of Earth's ice packs, and the response of polar ecosystems. A brief video of a recent Antarctic expedition where sea ice properties were measured will be shown. Supported by NSF and ONR.

  18. Impact of sea ice initialization on sea ice and atmosphere prediction skill on seasonal timescales

    Science.gov (United States)

    Guemas, V.; Chevallier, M.; Déqué, M.; Bellprat, O.; Doblas-Reyes, F.

    2016-04-01

    We present a robust assessment of the impact of sea ice initialization from reconstructions of the real state on the sea ice and atmosphere prediction skill. We ran two ensemble seasonal prediction experiments from 1979 to 2012 : one using realistic sea ice initial conditions and another where sea ice is initialized from a climatology, with two forecast systems. During the melting season in the Arctic Ocean, sea ice forecasts become skilful with sea ice initialization until 3-5 months ahead, thanks to the memory held by sea ice thickness. During the freezing season in both the Arctic and Antarctic Oceans, sea ice forecasts are skilful for 7 and 2 months, respectively, with negligible differences between the two experiments, the memory being held by the ocean heat content. A weak impact on the atmosphere prediction skill is obtained.

  19. GHRSST Level 4 EUR Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily by Ifremer/CERSAT (France) using optimal...

  20. GHRSST Level 4 ODYSSEA Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

  1. First biological measurements of deep-sea corals from the Red Sea.

    KAUST Repository

    Roder, Cornelia

    2013-10-03

    It is usually assumed that metabolic constraints restrict deep-sea corals to cold-water habitats, with \\'deep-sea\\' and \\'cold-water\\' corals often used as synonymous. Here we report on the first measurements of biological characters of deep-sea corals from the central Red Sea, where they occur at temperatures exceeding 20°C in highly oligotrophic and oxygen-limited waters. Low respiration rates, low calcification rates, and minimized tissue cover indicate that a reduced metabolism is one of the key adaptations to prevailing environmental conditions. We investigated four sites and encountered six species of which at least two appear to be undescribed. One species is previously reported from the Red Sea but occurs in deep cold waters outside the Red Sea raising interesting questions about presumed environmental constraints for other deep-sea corals. Our findings suggest that the present understanding of deep-sea coral persistence and resilience needs to be revisited.

  2. First biological measurements of deep-sea corals from the Red Sea.

    Science.gov (United States)

    Roder, C; Berumen, M L; Bouwmeester, J; Papathanassiou, E; Al-Suwailem, A; Voolstra, C R

    2013-10-03

    It is usually assumed that metabolic constraints restrict deep-sea corals to cold-water habitats, with 'deep-sea' and 'cold-water' corals often used as synonymous. Here we report on the first measurements of biological characters of deep-sea corals from the central Red Sea, where they occur at temperatures exceeding 20°C in highly oligotrophic and oxygen-limited waters. Low respiration rates, low calcification rates, and minimized tissue cover indicate that a reduced metabolism is one of the key adaptations to prevailing environmental conditions. We investigated four sites and encountered six species of which at least two appear to be undescribed. One species is previously reported from the Red Sea but occurs in deep cold waters outside the Red Sea raising interesting questions about presumed environmental constraints for other deep-sea corals. Our findings suggest that the present understanding of deep-sea coral persistence and resilience needs to be revisited.

  3. Increased CO2 uptake due to sea ice growth and decay in the Nordic Seas

    DEFF Research Database (Denmark)

    Rysgaard, S.; Bendtsen, J.; Pedersen, L. T.

    2009-01-01

    uptake in the Nordic Seas is currently unknown. We present evidence from 50 localities in the Arctic Ocean that dissolved inorganic carbon is rejected together with brine from growing sea ice and that sea ice melting during summer is rich in carbonates. Model calculations show that melting of sea ice......The uptake rates of atmospheric CO2 in the Nordic Seas are among the highest in the world's oceans. This has been ascribed mainly to a strong biological drawdown, but chemical processes within the sea ice itself have also been suggested to play a role. The importance of sea ice for the carbon...... exported from the Arctic Ocean into the East Greenland current and the Nordic Seas plays an important and overlooked role in regulating the surface water partial pressure of CO2 and increases the seasonal CO2 uptake in the area by approximately 50%....

  4. Oceanographic cruise: Coral Sea, Arafura Sea, and Java Trench, April - May 1969 (NODC Accession 7100914)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report contains oceanographic data which was obtained aboard HMAS DIAMANTINA during an oceanographic cruise in the Coral Sea, Arafura Sea, and Java Trench...

  5. Sea otter health: challenging a pet hypothesis

    Science.gov (United States)

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  6. Physical oceanography of the Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Leppaeranta, Matti [Helsinki Univ. (Finland). Dept. of Physics; Myrberg, Kai [Finnish Institute of Marine Research, Helsinki (Finland)

    2009-07-01

    The Baltic Sea oceanographic research community is wide and the research history is over 100 years old. Nevertheless, there is still no single, coherent book on the physical oceanography of the Baltic Sea as a whole. There is a strong need for such a book, coming from working oceanographers as well as the university teaching programmes in advanced undergraduate to graduate levels. In the regional conference series in physical oceanography (Baltic Sea Science Conference, Baltic Sea Oceanographers' conference, Baltex-conferences) about 500 scientists take part regularly. Even more scientists work in the fields of marine biology, chemistry and the environment, and they need information on the physics of the Baltic Sea as well. There are nine countries bordering on the Baltic Sea and five more in the runoff area. The Baltic Sea as a source of fish, means of transportation and leisure activities is highly important to the regional society. In the runoff area there are a total of 85 million people. Research and protection strategies need to be developed, as the Baltic Sea is probably the most polluted sea in the world. Since the Baltic Sea has become an inner sea of the EU (apart from small shore parts of Russia in Petersburg and Kaliningrad), it is anticipated that the importance of the region will consequently rise. The book will arouse interest among students, scientists and decision makers involved with the Baltic problems. It will also give important background information for those working with biogeochemical processes in the Baltic Sea, because the physical forcing for those processes is of vital importance. (orig.)

  7. Sea Surface Salinity : Research Challenges and Opportunities

    Science.gov (United States)

    Halpern, David; Lagerloef, Gary; Font, Jordi

    2012-01-01

    Sea surface salinity (SSS) can be important in regulating sea surface temperature (SST). Two technological breakthrough satellite SSS missions, Aquarius and Soil Moisture and Ocean Salinity (SMOS), are currently producing high-quality SSS data. This paper provides an overview of the importance of SSS for weather and climate applications and describes the Aquarius and SMOS missions. The newness of adequately sampled SSS data prompted a first-time at-sea field campaign devoted to improved understanding of SSS variations.

  8. Navigation Issues in the South China Sea

    OpenAIRE

    2005-01-01

    The South China Sea is one of the most important sea lanes with numerous competing sovereignty disputes. The freedom of navigation in this region is critical to all major trading States in the world. After an introduction to the navigational regimes of UNCLOS, this article describes the whole navigation situation in this region, by separately introducing the navigation issues in the territorial sea, straits, archipelagic waters and the Spratly area. Meanwhile, since the legal status of the ma...

  9. Comparison among four kinds of data of sea surface wind stress in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    谢强; 王卫强; 毛庆文

    2002-01-01

    By using remote sensing (ERS) data, FSU data, GOADS data and Hellerman & Rcsenstein objective analysis data to analyze the sea surface wind stress in the South China Sea, it is found that the remote sensing data have higher resolution and more reasonable values. Therefore we suggest that remote sensing data be chosen in the study of climatological features of sea surface wind stress and its seasonal variability in the South China Sea, especially in the study of small and middle scale eddies.

  10. Arctic tides from GPS on sea ice

    DEFF Research Database (Denmark)

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing...... of Global Positioning System (GPS) buoys placed on sea-ice at five different sites north of Greenland for the study of sea level height and tidal analysis to improve tidal models in the Central Arctic. The GPS measurements are compared with the Arctic tidal model AOTIM-5, which assimilates tide...

  11. Quantification of ikaite in Antarctic sea ice

    Directory of Open Access Journals (Sweden)

    M. Fischer

    2012-02-01

    Full Text Available Calcium carbonate precipitation in sea ice can increase pCO2 during precipitation in winter and decrease pCO2 during dissolution in spring. CaCO3 precipitation in sea ice is thought to potentially drive significant CO2 uptake by the ocean. However, little is known about the quantitative spatial and temporal distribution of CaCO3 within sea ice. This is the first quantitative study of hydrous calcium carbonate, as ikaite, in sea ice and discusses its potential significance for the carbon cycle in polar oceans. Ice cores and brine samples were collected from pack and land fast sea ice between September and December 2007 during an expedition in the East Antarctic and another off Terre Adélie, Antarctica. Samples were analysed for CaCO3, Salinity, DOC, DON, Phosphate, and total alkalinity. A relationship between the measured parameters and CaCO3 precipitation could not be observed. We found calcium carbonate, as ikaite, mostly in the top layer of sea ice with values up to 126 mg ikaite per liter melted sea ice. This potentially represents a contribution between 0.12 and 9 Tg C to the annual carbon flux in polar oceans. The horizontal distribution of ikaite in sea ice was heterogenous. We also found the precipitate in the snow on top of the sea ice.

  12. On sea level - ice sheet interactions

    Science.gov (United States)

    Gomez, Natalya Alissa

    This thesis focuses on the physics of static sea-level changes following variations in the distribution of grounded ice and the influence of these changes on the stability and dynamics of marine ice sheets. Gravitational, deformational and rotational effects associated with changes in grounded ice mass lead to markedly non-uniform spatial patterns of sea-level change. I outline a revised theory for computing post-glacial sea-level predictions and discuss the dominant physical effects that contribute to the patterns of sea-level change associated with surface loading on different timescales. I show, in particular, that a large sea-level fall (rise) occurs in the vicinity of a retreating (advancing) ice sheet on both short and long timescales. I also present an application of the sea-level theory in which I predict the sea-level changes associated with a new model of North American ice sheet evolution and consider the implications of the results for efforts to establish the sources of Meltwater Pulse 1A. These results demonstrate that viscous deformational effects can influence the amplitude of sea-level changes observed at far-field sea-level sites, even when the time window being considered is relatively short (≤ 500 years). Subsequently, I investigate the feedback of sea-level changes on marine ice-sheet stability and dynamics by coupling a global sea-level model to ice-sheet models of increasing complexity. To begin, I incorporate gravitationally self-consistent sea-level changes into an equilibrium marine ice-sheet stability theory to show that the sea-level changes have a stabilizing influence on ice-sheet retreat. Next, I consider the impact of the stabilizing mechanism on the timescale of ice-sheet retreat using a 1D dynamic coupled ice sheet - sea level model. Simulations with the coupled model, which incorporate viscoelastic deformation of the solid Earth, show that local sea-level changes at the grounding line act to slow, and in some cases, halt

  13. Physicochemical Studies of the Sea Surface Microlayer.

    Science.gov (United States)

    Zhengbin; Liansheng; Zhijian; Jun; Haibing

    1998-08-15

    The sea surface microlayer and its thickness are theoretically analyzed. A multiple-layer model of the sea surface microlayer is proposed. Through in situ and laboratory imitation experiments using glass plate, rotating drum, screen, and funnel samplers, the relationships between pH, surface tension, the concentrations of dissolved trace metals Cu and Pb, phosphate, and particulate and sampling thicknesses are carefully investigated. The apparent sampling thickness of the sea surface microlayer is determined to be 50 +/- 10 µm, which is basically consistent with the mean thickness of the liquid boundary film in the models of gas exchange across the sea surface. Copyright 1998 Academic Press.

  14. Parasites in the Wadden Sea food web

    Science.gov (United States)

    Thieltges, David W.; Engelsma, Marc Y.; Wendling, Carolin C.; Wegner, K. Mathias

    2013-09-01

    While the free-living fauna of the Wadden Sea has received much interest, little is known on the distribution and effects of parasites in the Wadden Sea food web. However, recent studies on this special type of trophic interaction indicate a high diversity of parasites in the Wadden Sea and suggest a multitude of effects on the hosts. This also includes effects on specific predator-prey relationships and the general structure of the food web. Focussing on molluscs, a major group in the Wadden Sea in terms of biomass and abundance and an important link between primary producers and predators, we review existing studies and exemplify the ecological role of parasites in the Wadden Sea food web. First, we give a brief inventory of parasites occurring in the Wadden Sea, ranging from microparasites (e.g. protozoa, bacteria) to macroparasites (e.g. helminths, parasitic copepods) and discuss the effects of spatial scale on heterogeneities in infection levels. We then demonstrate how parasites can affect host population dynamics by acting as a strong mortality factor, causing mollusc mass mortalities. In addition, we will exemplify how parasites can mediate the interaction strength of predator-prey relationships and affect the topological structure of the Wadden Sea food web as a whole. Finally, we highlight some ongoing changes regarding parasitism in the Wadden Sea in the course of global change (e.g. species introduction, climate change) and identify important future research questions to entangle the role of parasites in the Wadden Sea food web.

  15. Dynamic Singularity Spectrum Distribution of Sea Clutter

    Science.gov (United States)

    Xiong, Gang; Yu, Wenxian; Zhang, Shuning

    2015-12-01

    The fractal and multifractal theory have provided new approaches for radar signal processing and target-detecting under the background of ocean. However, the related research mainly focuses on fractal dimension or multifractal spectrum (MFS) of sea clutter. In this paper, a new dynamic singularity analysis method of sea clutter using MFS distribution is developed, based on moving detrending analysis (DMA-MFSD). Theoretically, we introduce the time information by using cyclic auto-correlation of sea clutter. For transient correlation series, the instantaneous singularity spectrum based on multifractal detrending moving analysis (MF-DMA) algorithm is calculated, and the dynamic singularity spectrum distribution of sea clutter is acquired. In addition, we analyze the time-varying singularity exponent ranges and maximum position function in DMA-MFSD of sea clutter. For the real sea clutter data, we analyze the dynamic singularity spectrum distribution of real sea clutter in level III sea state, and conclude that the radar sea clutter has the non-stationary and time-varying scale characteristic and represents the time-varying singularity spectrum distribution based on the proposed DMA-MFSD method. The DMA-MFSD will also provide reference for nonlinear dynamics and multifractal signal processing.

  16. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    Directory of Open Access Journals (Sweden)

    R. A. Ibrayev

    2010-03-01

    Full Text Available A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. The model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  17. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    Directory of Open Access Journals (Sweden)

    R. A. Ibrayev

    2009-09-01

    Full Text Available A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. Model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  18. Sea breeze-induced wind sea growth in the central west coast of India.

    Digital Repository Service at National Institute of Oceanography (India)

    Aboobacker, V.M.; Seemanth, M.; Samiksha, S.V.; Sudheesh, K.; Kerkar, J.; Vethamony, P.

    in the northwest direction, and grow progressively while propagating towards the coast. Relationships between wind speed and wind sea height have been derived, and they fairly explain the generation of wind seas by the sea breeze system. Since, the land breeze...

  19. Morphotype patterns of Norwegian Sea deep-sea benthic foraminifera and ecological implications

    Science.gov (United States)

    Corliss, Bruce H.; Chen, Christina

    1988-08-01

    Deep-sea benthic foraminifera from Norwegian Sea surface sediments are classified into morphotypes on the basis of test shape and nature of test coiling and show distinct patterns with water depth. The morphotype data are used to determine microhabitat patterns of the foraminifera, which are suggested to be related to the organic-carbon content of the surficial deep-sea sediments.

  20. Sea Turtle Conservation on Bonaire. Sea Turtle Club Bonaire 1997. Project Report

    NARCIS (Netherlands)

    Schuit, M.; Put, van A.L.L.M.; Valkering, N.P.; Eijck, van T.J.W.

    1998-01-01

    The Sea Turtle Club Bonaire (STCB) is a non-governmental, non-profit organization. Its main goal is the conservation of the sea turtles that occur on Bonaire. To reach this goal, annual projects are undertaken, such as research and the promotion of public awareness on sea turtle conservation. The ST

  1. Long Term Sea Level Change and Water Mass Balance in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    RONG Zengrui; LIU Yuguang; ZONG Haibo; XIU Peng

    2009-01-01

    Sea level anomalies observed by altimeter during the 1993-2006 period, thermosterie sea level anomalies estimated by using subsurface temperature data produced by Ishii and SODA reanalysis data, tide gauge records and HOAPS freshwater flux data were analyzed to investigate the long term sea level change and the water mass balance in the South China Sea. The altimeter-observed sea level showed a rising rate of (3.5±0.9)mm yr-1 during the period 1993-2006, but this figure was considered to have been highly distorted by the relatively short time interval and the large inter-decadal variability, which apparently exists in both the thermosteric sea level and the observed sea level. Long term thermosteric sea level from 1945 to 2004 gave a rising rate of 0.15±0.06 mmyr-1. Tide gauge data revealed this discrepancy and the regional distributions of the sea-level trends. Both the 'real' and the thermosteric sea level showed a good correspondence to ENSO: decreasing during E1 Nifio years and increasing during La Nina years. Amplitude and phase differences between the 'real' sea level and the thermosteic sea level were substantially revealed on both seasonal and interannual time scales. As one of the possible factors, the freshwater flux might play an important role in balancing the water mass.

  2. Ordenisaajate seas seisab arvukalt riigiteenistujaid

    Index Scriptorium Estoniae

    2004-01-01

    Riikliku autasu saajate nimekiri. Teenetemärgi saajate seas muusikud: Valgetähe III klass Henn Tiivel. Valgetähe IV klass Johannes Jürisson, Valeri Petrov, Aadu Regi, Helga Surva, Kalle Tamra. Valgetähe V klass Kalev Kuljus, Jaan Mikkel, Heidi Mägi, Heino Mähar, Sigrid Orusaar, Aarne Saluveer, Heli Lääts, Ludmilla Toon. Valgetähe medal Endla Jaanus, Ralf Kaup, Aadu Kukk, Tiit Köster, Heino Pehk, Tiiu Schüts

  3. Filling regulatory gaps in high seas fisheries: discrete high seas fish stocks, deep-sea fisheries and vulnerable marine ecosystems

    NARCIS (Netherlands)

    Takei, Y.

    2008-01-01

    The present study examines the legal regime of high seas fisheries with a view to identifying regulatory gaps. The main research questions are as follows: 1. What general principles are applicable to high seas fisheries?; 2. What implications do these general principles have for new challenges in th

  4. Deep-sea pollen research in China

    Institute of Scientific and Technical Information of China (English)

    SUN Xiangjun; LUO Yunli; CHEN Huaicheng

    2003-01-01

    This paper briefly presents the progress of deep-sea pollen research in China since the beginning ofninetieths of the last Century. All the deep-sea pollen contri-butions mainly come from the South China Sea (SCS) andthe East China Sea (ECS). The German-Chinese joint cruise(Sonne 95) and ODP 184 cruise initiated by Chinese scientistsin the SCS provided excellent material for the deep-sea pol-len research. So far a number of pollen results of 20-30 kaand million years from the SCS have been published. A couple of deep-sea pollen records from Okinawa Through of the ECS also came out. The high resolution pollen records obtained from the continuous deposits with high sedimentation rates and reliable age control of the deep-sea sediments provided a high time resolution history (hundred to millennial scales) of vegetation, environment and monsoon evolution of the pollen source areas (southern China and Japan). Spectral analysis of deep-sea pollen records from the SCS discovered orbital (100, 41, 23, 10 ka) and suborbital cyclicities (Heinrich and Dansgaard/Oscheger-O/D events) in the vege-tation changes. Moreover, cross spectral analysis showed that the trend of vegetation changes in northern SCS was regulated mainly by changes of the ice volume in the Northern Hemisphere. The pollen record of the last 20 ka from the Okinawa Through of the ECS indicates that the marine environmental change lagged that on the terrestrail by about 1000 year. The asynchronous environmental changes between land and sea were probably caused by the time difference in thermohaline circulation. This study underscored the role of the deep-sea plant fossils as a bridge across the land and sea.

  5. Air-sea CO2 fluxes on the Bering Sea shelf

    Directory of Open Access Journals (Sweden)

    M. A. Jeffries

    2011-05-01

    Full Text Available There have been few previous studies of surface seawater CO2 partial pressure (pCO2 variability and air-sea CO2 gas exchange rates for the Bering Sea shelf. In 2008, spring and summertime observations were collected in the Bering Sea shelf as part of the Bering Sea Ecological Study (BEST. Our results indicate that the Bering Sea shelf was close to neutral in terms of CO2 sink-source status in springtime due to relatively small air-sea CO2 gradients (i.e., ΔpCO2 and sea-ice cover. However, by summertime, very low seawater pCO2 values were observed and much of the Bering Sea shelf became strongly undersaturated with respect to atmospheric CO2 concentrations. Thus the Bering Sea shelf transitions seasonally from mostly neutral conditions to a strong oceanic sink for atmospheric CO2 particularly in the "green belt" region of the Bering Sea where there are high rates of phytoplankton primary production (PPand net community production (NCP. Ocean biological processes dominate the seasonal drawdown of seawater pCO2 for large areas of the Bering Sea shelf, with the effect partly countered by seasonal warming. In small areas of the Bering Sea shelf south of the Pribilof Islands and in the SE Bering Sea, seasonal warming is the dominant influence on seawater pCO2, shifting localized areas of the shelf from minor/neutral CO2 sink status to neutral/minor CO2 source status, in contrast to much of the Bering Sea shelf. Overall, we compute that the Bering Sea shelf CO2 sink in 2008 was 157 ± 35 Tg C yr−1 (Tg = 1012 g C and thus a strong sink for CO2.

  6. A Heavy Sea Fog Event over the Yellow Sea in March 2005:Analysis and Numerical Modeling

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, a heavy sea fog episode that occurred over the Yellow Sea on 9 March 2005 is investigated.The sea fog patch, with a spatial scale of several hundred kilometers at its mature stage, reduced visibility along the Shandong Peninsula coast to 100 m or much less at some sites. Satellite images, surface observations and soundings at islands and coasts, and analyses from the Japan Meteorology Agency (JMA) are used to describe and analyze this event. The analysis indicates that this sea fog can be categorized as advection cooling fog. The main features of this sea fog including fog area and its movement are reasonably reproduced by the Fifth-generation Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5). Model results suggest that the formation and evolution of this event can be outlined as:(1) southerly warm/moist advection of low-level air resulted in a strong sea-surface-based inversion with a thickness of about 600 m; (2) when the inversion moved from the warmer East Sea to the colder Yellow Sea, a thermal internal boundary layer (TIBL) gradually formed at the base of the inversion while the sea fog grew in response to cooling and moistening by turbulence mixing; (3) the sea fog developed as the TIBL moved northward and (4) strong northerly cold and dry wind destroyed the TIBL and dissipated the sea fog. The principal findings of this study are that sea fog forms in response to relatively persistent southerly warm/moist wind and a cold sea surface, and that turbulence mixing by wind shear is the primary mechanism for the cooling and moistening the marine layer. In addition, the study of sensitivity experiments indicates that deterministic numerical modeling offers a promising approach to the prediction of sea fog over the Yellow Sea but it may be more efficient to consider ensemble numerical modeling because of the extreme sensitivity to model input.

  7. Multisensor Analyzed Sea Ice Extent - Northern Hemisphere (MASIE-NH)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Multisensor Analyzed Sea Ice Extent Northern Hemisphere (MASIE-NH) products provide measurements of daily sea ice extent and sea ice edge boundary for the...

  8. Snow on Antarctic sea ice

    Science.gov (United States)

    Massom, Robert A.; Eicken, Hajo; Hass, Christian; Jeffries, Martin O.; Drinkwater, Mark R.; Sturm, Matthew; Worby, Anthony P.; Wu, Xingren; Lytle, Victoria I.; Ushio, Shuki; Morris, Kim; Reid, Phillip A.; Warren, Stephen G.; Allison, Ian

    2001-08-01

    Snow on Antarctic sea ice plays a complex and highly variable role in air-sea-ice interaction processes and the Earth's climate system. Using data collected mostly during the past 10 years, this paper reviews the following topics: snow thickness and snow type and their geographical and seasonal variations; snow grain size, density, and salinity; frequency of occurrence of slush; thermal conductivity, snow surface temperature, and temperature gradients within snow; and the effect of snow thickness on albedo. Major findings include large regional and seasonal differences in snow properties and thicknesses; the consequences of thicker snow and thinner ice in the Antarctic relative to the Arctic (e.g., the importance of flooding and snow-ice formation); the potential impact of increasing snowfall resulting from global climate change; lower observed values of snow thermal conductivity than those typically used in models; periodic large-scale melt in winter; and the contrast in summer melt processes between the Arctic and the Antarctic. Both climate modeling and remote sensing would benefit by taking account of the differences between the two polar regions.

  9. BACTERIAL DESEASES IN SEA FISH

    Directory of Open Access Journals (Sweden)

    Ivančica Strunjak-Perović

    1997-10-01

    Full Text Available With development of the fish culturing in the sea, the interest in their health also increased. The reason for this are diseases or rather mortality that occur in such controlled cultures and cause great economic losses. By growing large quantities of fish in rather small species, natural conditions are changed, so fish is more sensitive and prone to infection agents (viruses, bacteria, parasites. Besides, a large fish density in the cultural process accelerates spreading if the diseases, but also enables a better perception of them. In wild populations sick specimen very quickly become predator’s prey, witch makes it difficult to note any pathological changes in such fish. There are lots of articles on viral, bacterial and parasitic diseases nowdays, but this work deals exclusively with bacterial deseases that occur in the controlled sea cultures (vibriosis, furunculosis, pastherelosis, nocardiosis, mycobaceriosis, edwardsielosis, yersiniosis, deseases caused by bacteria of genera Flexibacter, Pseudomonas, Aeromonas, Streptococus and bacteria nephryithis. Yet, the knowledge of these deseases vary, depending on wether a fish species is being cultured for a longer period of time or is only being introduced in the controlled culture.

  10. Mapping of sea bottom topography

    Science.gov (United States)

    Calkoen, C. J.; Wensink, G. J.; Hesselmans, G. H. F. M.

    1992-01-01

    Under suitable conditions the bottom topography of shallow seas is visible in remote sensing radar imagery. Two experiments were performed to establish which remote sensing technique or combination yields optimal imaging of bottom topography and which hydro-meteorological conditions are favorable. A further goal is to gain experience with these techniques. Two experiments were performed over an area in the North Sea near the measuring platform Meetpost Noordwijk (MPN). The bottom topography in the test area is dominated by sand waves. The crests of the sand waves are perpendicular to the coast line and the dominating (tidal-)current direction. A 4x4 sq km wide section of the test area was studied in more detail. The first experiment was undertaken on 16 Aug. 1989. During the experiment the following remote sensing instruments were used: Landsat-Thematic Mapper, and NASA/JPL Airborne Imaging Radar (AIR). The hydro-meteorological conditions; current, wind, wave, and air and water temperature were monitored by MPN, a ship of Rijkswaterstaat (the OCTANS), and a pitch-and-roll WAVEC-buoy. The second experiment took place on 12 July 1992. During this experiment data were collected with the NASA/JPL polarimetric synthetic aperture radar (SAR), and a five-band helicopter-borne scatterometer. Again the hydro-meteorological conditions were monitored at MPN and the OCTANS. Furthermore, interferometric radar data were collected.

  11. CO2 and sea level

    Science.gov (United States)

    Bell, Peter M.

    There is considerable discussion currently about the potential effects of carbon dioxide build-up in the atmosphere over the next several decades. The sources of information are two Government funded reports, one by the National Research Council (NRC), the other by the Environment Protection Agency (EPA), both were released within the last five months. The reports were described recently as being conservative, although the consequences of the resulting greenhouse effects are deemed inevitable. Atmospheric warming on a global scale of as much as 5°C cannot be avoided, only perhaps delayed by a few years at best (Environ. Sci. Technol, 18, 45A-46A, 1984). The cause is the burning of fossil fuels. Oil will not be too important because its supplies are predictably exhausted on the time scale of 50-100 years. Coal burning is considered as the main source of carbon dioxide. Among the more spectacular results of a global temperature rise over the next 100 years is the expected rise in sea level of a minimum of 70 cm (Oceanus, Winter, 1983/84). If the West Antarctic Ice Sheet breaks up and melts, the rise could be in the several meter range. Sea level rose only 15 cm in the past century.

  12. Early-Holocene warming in Beringia and its mediation by sea-level and vegetation changes

    Science.gov (United States)

    Bartlein, P.J.; Edwards, M.E.; Hostetler, Steven W.; Shafer, Sarah; Anderson, P.M.; Brubaker, L. B; Lozhkin, A. V

    2015-01-01

    Arctic land-cover changes induced by recent global climate change (e.g., expansion of woody vegetation into tundra and effects of permafrost degradation) are expected to generate further feedbacks to the climate system. Past changes can be used to assess our understanding of feedback mechanisms through a combination of process modeling and paleo-observations. The subcontinental region of Beringia (northeastern Siberia, Alaska, and northwestern Canada) was largely ice-free at the peak of deglacial warming and experienced both major vegetation change and loss of permafrost when many arctic regions were still ice covered. The evolution of Beringian climate at this time was largely driven by global features, such as the amplified seasonal cycle of Northern Hemisphere insolation and changes in global ice volume and atmospheric composition, but changes in regional land-surface controls, such as the widespread development of thaw lakes, the replacement of tundra by deciduous forest or woodland, and the flooding of the Bering–Chukchi land bridge, were probably also important. We examined the sensitivity of Beringia's early Holocene climate to these regional-scale controls using a regional climate model (RegCM). Lateral and oceanic boundary conditions were provided by global climate simulations conducted using the GENESIS V2.01 atmospheric general circulation model (AGCM) with a mixed-layer ocean. We carried out two present-day simulations of regional climate – one with modern and one with 11 ka geography – plus another simulation for 6 ka. In addition, we performed five ~ 11 ka climate simulations, each driven by the same global AGCM boundary conditions: (i) 11 ka Control, which represents conditions just prior to the major transitions (exposed land bridge, no thaw lakes or wetlands, widespread tundra vegetation), (ii) sea-level rise, which employed present-day continental outlines, (iii) vegetation change, with deciduous needleleaf and deciduous broadleaf boreal

  13. Early-Holocene warming in Beringia and its mediation by sea-level and vegetation changes

    Directory of Open Access Journals (Sweden)

    P. J. Bartlein

    2015-03-01

    Full Text Available Arctic land-cover changes (e.g., expansion of woody vegetation into tundra and effects of permafrost degradation that have been induced by recent global climate change are expected to generate further feedbacks to the climate system. Past changes can be used to assess our understanding of feedback mechanisms through a combination of process modelling and paleo-observations. The sub-continental region of Beringia (Northeast Siberia, Alaska, and northwestern Canada was largely ice-free at the peak of deglacial warming and experienced both major vegetation change and loss of permafrost when many arctic regions were still ice covered. The evolution of Beringian climate at this time was largely driven by global features, such as the amplified seasonal cycle of Northern Hemisphere insolation and changes in global ice volume and atmospheric composition, but changes in regional land-surface controls, such as the widespread development of thaw lakes, the replacement of tundra by deciduous forest or woodland, and the flooding of the Bering–Chukchi land bridge, were probably also important. We examined the sensitivity of Beringia's early Holocene climate to these regional-scale controls using a regional climate model (RegCM. Lateral and oceanic boundary conditions were provided by global climate simulations conducted using the GENESIS V2.01 atmospheric general circulation model (AGCM with a mixed-layer ocean. We carried out two present day simulations of regional climate, one with modern and one with 11 ka geography, plus another simulation for 6 ka. In addition, we performed five ∼11 ka climate simulations, each driven by the same global AGCM boundary conditions: (i 11 ka "Control", which represents conditions just prior to the major transitions (exposed land bridge, no thaw lakes or wetlands, widespread tundra vegetation, (ii sea-level rise, which employed present day continental outlines, (iii vegetation change, with deciduous needleleaf and

  14. Early-Holocene warming in Beringia and its mediation by sea-level and vegetation changes

    Science.gov (United States)

    Bartlein, P. J.; Edwards, M. E.; Hostetler, S. W.; Shafer, S. L.; Anderson, P. M.; Brubaker, L. B.; Lozhkin, A. V.

    2015-09-01

    Arctic land-cover changes induced by recent global climate change (e.g., expansion of woody vegetation into tundra and effects of permafrost degradation) are expected to generate further feedbacks to the climate system. Past changes can be used to assess our understanding of feedback mechanisms through a combination of process modeling and paleo-observations. The subcontinental region of Beringia (northeastern Siberia, Alaska, and northwestern Canada) was largely ice-free at the peak of deglacial warming and experienced both major vegetation change and loss of permafrost when many arctic regions were still ice covered. The evolution of Beringian climate at this time was largely driven by global features, such as the amplified seasonal cycle of Northern Hemisphere insolation and changes in global ice volume and atmospheric composition, but changes in regional land-surface controls, such as the widespread development of thaw lakes, the replacement of tundra by deciduous forest or woodland, and the flooding of the Bering-Chukchi land bridge, were probably also important. We examined the sensitivity of Beringia's early Holocene climate to these regional-scale controls using a regional climate model (RegCM). Lateral and oceanic boundary conditions were provided by global climate simulations conducted using the GENESIS V2.01 atmospheric general circulation model (AGCM) with a mixed-layer ocean. We carried out two present-day simulations of regional climate - one with modern and one with 11 ka geography - plus another simulation for 6 ka. In addition, we performed five ~ 11 ka climate simulations, each driven by the same global AGCM boundary conditions: (i) 11 ka Control, which represents conditions just prior to the major transitions (exposed land bridge, no thaw lakes or wetlands, widespread tundra vegetation), (ii) sea-level rise, which employed present-day continental outlines, (iii) vegetation change, with deciduous needleleaf and deciduous broadleaf boreal

  15. Winter cooling in the northern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Prasad, T.G.

    forcing that leads to the observed high productivity during winter in the northern Arabian Sea. The weak northerly winds and increased solar insolation during the inter-monsoon period, led to the development of a highly stratified upper layer with warm sea...

  16. The South Pole and the Ross Sea

    Science.gov (United States)

    2002-01-01

    This image shows a rare clear view of the South Pole (lower right) and the Ross Sea, Antarctica. The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) acquired the scene on December 26, 2001. The geographic South Pole is located in the center of Antarctica, at an altitude of 2,900 meters (9,300 feet). It rests on a continent-wide ice sheet that is 2,870 m thick, with the underlying bedrock only 30 m (98 feet) above sea level. The ice underlying the South Pole is as much as 140,000 years old, and is currently accumulating at about 82 cm (32 inches) per year. Roughly 2,500 km (1,550 miles) away is the green water of the Ross Sea, which indicates the presence of large numbers of phytoplankton. This is a highly productive part of the world's oceans. Also note the ice gathered around McMurdo Sound, seen toward the lefthand shoreline of the Ross Sea, at the edge of the Ross Ice Shelf. According to National Science Foundation researchers, this ice is making it difficult for penguins to reach their food supply. Separating the continental Antarctic ice sheet from the Ross Sea are the Queen Maud Mountains and the Ross Ice Shelf. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  17. Sea level rise: A literature survey

    NARCIS (Netherlands)

    Oude Essink, G.H.P.

    1992-01-01

    In order to assess the impact of sea level rise on Water Management, it is useful to understand the mechanisrns that determine the level of the sea. In this study, a literature survey is executed to analyze these mechanisms. Climate plays a centra! role in these mechanisms, Climate mainly changes du

  18. Mapping of the air-sea CO

    NARCIS (Netherlands)

    Yasunaka, S.; Murata, A.; Watanabe, E.; Chierici, M.; Fransson, A.; van Heuven, S.; Hoppema, M.; Ishii, M.; Johannessen, T.; Kosugi, N.; Lauvset, S.K.; Mathis, J.T.; Nishino, S.; Omar, A.M.; Olsen, A.; Sasano, D.; Takahashi, T.; Wanninkhof, R.

    2016-01-01

    We produced 204 monthly maps of the air–sea CO2 flux in the Arctic north of 60°N, including the Arctic Ocean and its adjacent seas, from January 1997 to December 2013 by using a self-organizing map technique. The partial pressure of CO2 (pCO2) in surface water data were obtained by shipboard underwa

  19. Sea energy; Energie de la mer

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2004-07-01

    The tidal and wave power of the sea could offer electric power for many towns and villages of seashore. This document presents the possibilities of electric power production from the sea energy (submarine wind turbines, tidal energy and wave energy) and the research programs in the world. (A.L.B.)

  20. Sea Ice Mapping using Unmanned Aerial Systems

    Science.gov (United States)

    Solbø, S.; Storvold, R.

    2011-12-01

    Mapping of sea ice extent and sea ice features is an important task in climate research. Since the arctic coastal and oceanic areas have a high probability of cloud coverage, aerial platforms are superior to satellite measurements for high-resolution optical measurements. However, routine observations of sea ice conditions present a variety of problems using conventional piloted aircrafts. Specially, the availability of suitable aircrafts for lease does not cover the demand in major parts of the arctic. With the recent advances in unmanned aerial systems (UAS), there is a high possibility of establishing routine, cost effective aerial observations of sea ice conditions in the near future. Unmanned aerial systems can carry a wide variety of sensors useful for characterizing sea-ice features. For instance, the CryoWing UAS, a system initially designed for measurements of the cryosphere, can be equipped with digital cameras, surface thermometers and laser altimeters for measuring freeboard of ice flows. In this work we will present results from recent CryoWing sea ice flights on Svalbard, Norway. The emphasis will be on data processing for stitching together images acquired with the non-stabilized camera payload, to form high-resolution mosaics covering large spatial areas. These data are being employed to map ice conditions; including ice and lead features and melt ponds. These high-resolution mosaics are also well suited for sea-ice mechanics, classification studies and for validation of satellite sea-ice products.

  1. Greenhouse warming and changes in sea level

    NARCIS (Netherlands)

    Oerlemans, J.

    1989-01-01

    It is likely that the anticipated warming due to the effect of increasing concentration of carbon dioxide and other greenhouse gases will lead to a further and faster rise in world mean sea level. There are many processes in the climate system controlling sea level, but the most important factors in

  2. Seasonal variability in the Baltic Sea level

    Directory of Open Access Journals (Sweden)

    Marek Świrgoń

    2013-11-01

    Full Text Available Sea level is subject to spatial and temporal variability on different scales. In this paper we investigate seasonal variability in the open Baltic Sea level using daily satellite altimetry data for the period 1 January 1993-31 December 2010. Our results indicate that there is a well-pronounced seasonal cycle in the 18-year average sea level and in its standard deviation. The average annual SLA amplitude in the open Baltic Sea is about 18 cm. The seasonal cycle of the SLA in the Baltic Sea is asymmetric in shape. In the autumn and winter (about 240-260 days per year, the 18-year average daily SLA are higher than the 18-year annual average SLA. In the spring and summer (about 100-120 days per year, the 18-year average daily SLA are lower than the 18-year annual average SLA. A similar asymmetry of the seasonal cycle is not observed in the North Sea and North Atlantic SLA data. The annual pattern of the sea level variability in the Baltic Sea is evident if one considers multi-year average time series, but the cycle can be obscured in some years.

  3. Tritium level along Romanian Black Sea Coast

    Energy Technology Data Exchange (ETDEWEB)

    Varlam, C.; Stefanescu, I.; Popescu, I.; Faurescu, I. [National Inst. for Cryogenic and Isotopic Technologies, PO Box 10, Rm. Valcea, 24050 (Romania)

    2008-07-15

    Establishing the tritium level along the Romanian Black Sea Coast, after 10 years of exploitation of the nuclear power plant from Cernavoda, is a first step in evaluating its impact on the Black Sea ecosystem. The monitoring program consists of tritium activity concentration measurement in sea water and precipitation from Black Sea Coast between April 2005 and April 2006. The sampling points were spread over the Danube-Black Sea Canal - before the locks Agigea and Navodari, and Black Sea along the coast to the Bulgarian border. The average tritium concentration in sea water collected from the sampling locations had the value of 11.1 {+-} 2.1 TU, close to tritium concentration in precipitation. Although an operating nuclear power plant exists in the monitored area, the values of tritium concentration in two locations are slightly higher than those recorded elsewhere. To conclude, it could be emphasized that until now, Cernavoda NPP did not had any influence on the tritium concentration of the Black Sea Shore. (authors)

  4. The application of ERTS imagery to monitoring Arctic sea ice. [mapping ice in Bering Sea, Beaufort Sea, Canadian Archipelago, and Greenland Sea

    Science.gov (United States)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.

    1974-01-01

    The author has identified the following significant results. Because of the effect of sea ice on the heat balance of the Arctic and because of the expanding economic interest in arctic oil and minerals, extensive monitoring and further study of sea ice is required. The application of ERTS data for mapping ice is evaluated for several arctic areas, including the Bering Sea, the eastern Beaufort Sea, parts of the Canadian Archipelago, and the Greenland Sea. Interpretive techniques are discussed, and the scales and types of ice features that can be detected are described. For the Bering Sea, a sample of ERTS-1 imagery is compared with visual ice reports and aerial photography from the NASA CV-990 aircraft. The results of the investigation demonstrate that ERTS-1 imagery has substantial practical application for monitoring arctic sea ice. Ice features as small as 80-100 m in width can be detected, and the combined use of the visible and near-IR imagery is a powerful tool for identifying ice types. Sequential ERTS-1 observations at high latitudes enable ice deformations and movements to be mapped. Ice conditions in the Bering Sea during early March depicted in ERTS-1 images are in close agreement with aerial ice observations and photographs.

  5. Teaching Wide Sargasso Sea in New Jersey

    Science.gov (United States)

    Jolley, Susan Arpajian

    2005-01-01

    High school teacher Susan Arpajian Jolley emphasizes experience and understanding by using the related novels "Wide Sargasso Sea" and "Jane Eyre" to help her students travel into unfamiliar cultural territory. "Wide Sargasso Sea" relates to Caribbean history and culture, feminism, race relations, colonialism, and personal identity.

  6. Causes for contemporary regional sea level changes.

    Science.gov (United States)

    Stammer, Detlef; Cazenave, Anny; Ponte, Rui M; Tamisiea, Mark E

    2013-01-01

    Regional sea level changes can deviate substantially from those of the global mean, can vary on a broad range of timescales, and in some regions can even lead to a reversal of long-term global mean sea level trends. The underlying causes are associated with dynamic variations in the ocean circulation as part of climate modes of variability and with an isostatic adjustment of Earth's crust to past and ongoing changes in polar ice masses and continental water storage. Relative to the coastline, sea level is also affected by processes such as earthquakes and anthropogenically induced subsidence. Present-day regional sea level changes appear to be caused primarily by natural climate variability. However, the imprint of anthropogenic effects on regional sea level-whether due to changes in the atmospheric forcing or to mass variations in the system-will grow with time as climate change progresses, and toward the end of the twenty-first century, regional sea level patterns will be a superposition of climate variability modes and natural and anthropogenically induced static sea level patterns. Attribution and predictions of ongoing and future sea level changes require an expanded and sustained climate observing system.

  7. Alaska Program Point and Line Feature GIS Data from COMIDA, ANIMIDA and cANIMIDA Programs

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — Alaska Program Map Service contains point and line features from the following BOEM Alaska Region environmental monitoring programs: Chukchi Sea Offshore Monitoring...

  8. Modern populations, migrations, demography, trophics, and historical status of the Pacific walrus: Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Pacific walrus population inhabits the waters over the entire continental shelf of the Bering and Chukchi seas. That population is a natural resource of...

  9. Sea ice thickness estimation in the Bohai Sea using geostationary ocean color imager data

    Institute of Scientific and Technical Information of China (English)

    LIU Wensong; SHENG Hui; ZHANG Xi

    2016-01-01

    A method to estimate the thickness of the sea ice of the Bohai Sea is proposed using geostationary ocean color imager (GOCI) data and then applied to the dynamic monitoring of the sea ice thickness in the Bohai Sea during the winter of 2014 to 2015. First of all, a model is given between the GOCI shortwave broadband albedo and the reflectance of each band with high temporal resolution GOCI data. Then, the relationship model between the sea ice thickness and the GOCI shortwave broadband albedo is established and applied to the thickness extraction of the sea ice in the Bohai Sea. Finally, the sea ice thickness extraction method is tested by the results based on the MODIS data, thermodynamic empirical models (Lebedev and Zubov), and thein situ ice thickness data. The test results not only indicated that the sea ice thickness retrieval method based on the GOCI data was a good correlation (r2>0.86) with the sea ice thickness retrieved by the MODIS and thermodynamic empirical models, but also that the RMS is only 6.82 cm different from the thickness of the sea ice based on the GOCI andin situ data.

  10. Physical, optical, and chemical profile data from CTD casts collected from August 2005 to July 2012 from platforms Sever, Akademik Lavrentiev, and Professor Khromov in the Bering and Chukchi Seas in support of the Russian-American Long-term Census of the Arctic (RUSALCA) (NODC Accession 0125595)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of the joint US-Russian RUSALCA (Russian US Long-term Census of the Arctic Ocean) Program, a team of US and Russian scientists undertook oceanographic...

  11. Acoustics long-term passive monitoring using moored autonomous recorders in the Bering, Chukchi, and Western Beaufort Seas conducted by Alaska Fisheries Scientific Center, National Marine Mammal Laboratory from 2007-08-15 to 2015-04-30 (NCEI Accession 0143303)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has deployed long-term passive acoustic recorders in various locations in Alaskan waters and in the High Arctic to...

  12. The cooling and moistening effect on the formation of sea fog in the Huanghai Sea

    Institute of Scientific and Technical Information of China (English)

    HUANG Jian; ZHOU Faxiu

    2006-01-01

    With the sea surface observations from ICOADS for the years 1960~2002, the conditions of cooling, evaporation and water vapor transportation are analyzed and compared for the formation of seasonal sea fog in April-July in the Huanghai Sea. It is found that sea surface cooling is always existent during the fog seasons while sea surface evaporation only appears in April-June in the Huanghai Sea. Local evaporation alone is not sufficient to form fogs though it may lead to light ones. Water vapor transported from the low-latitudes accomplished by specific synoptic systems is the most important condition for sea fog formation. In general, the moistening effect is more important than the cooling one.

  13. On the measure of sea ice area from sea ice concentration data sets

    Science.gov (United States)

    Boccolari, Mauro; Parmiggiani, Flavio

    2015-10-01

    The measure of sea ice surface variability provides a fundamental information on the climatology of the Arctic region. Sea ice extension is conventionally measured by two parameters, i.e. Sea Ice Extent (SIE) and Sea Ice Area (SIA), both parameters being derived from Sea Ice Concentration (SIC) data sets. In this work a new parameter (CSIA) is introduced, which takes into account only the compact sea-ice, which is defined as the sea-ice having concentration at least equal the 70%. Aim of this study is to compare the performances of the two parameters, SIA and CSIA, in analyzing the trends of three monthly time-series of the whole Arctic region. The SIC data set used in this study was produced by the Institute of Environmental Physics of the University of Bremen and covers the period January 2003 - December 2014, i.e. the period in which the data set is built using the new AMSR passive microwave sensor.

  14. A sea temperature data assimilation system for the China Seas and adjacent areas

    Institute of Scientific and Technical Information of China (English)

    YOU Xiaobao; ZHOU Guangqing; ZHU Jiang; LI Rongfeng

    2003-01-01

    A sea temperature data assimilation system for the China Seas and adjacent areas is developed based on a nested regional ocean circulation model and variational optimal interpolation assimilation method. A 12-year assimilation experiment is performed by using the observational temperature profiles from World Ocean Database 1998 (WOD98) and ECMWF reanalysis surface wind stress. Experimental results indicate that the variational scheme shows good skill in assimilating the observed sea temperature into a regional ocean circulation model. Compared with simulation alone, the sea temperature data assimilation significantly improves the performance of a regional ocean model and obtains comprehensive description of the circulations in the China Seas and adjacent areas. Assimilation results, such as the strength and flowing axis of the Kuroshio, Yellow Sea Cold Water Mass and its corresponding horizontal circulation in summer and dipole eddies in the South China Sea in the late summer/early autumn and the eastward jet between them, are well consistent with the observed evidences.

  15. Captive sea turtle rearing inventory, feeding, and water chemistry in sea turtle rearing tanks at NOAA Galveston 1995-present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The database contains daily records of sea turtle inventories by species feeding rates type of food fed sick sea turtles sea turtles that have died log of tanks...

  16. Predictability of the Arctic sea ice edge

    Science.gov (United States)

    Goessling, H. F.; Tietsche, S.; Day, J. J.; Hawkins, E.; Jung, T.

    2016-02-01

    Skillful sea ice forecasts from days to years ahead are becoming increasingly important for the operation and planning of human activities in the Arctic. Here we analyze the potential predictability of the Arctic sea ice edge in six climate models. We introduce the integrated ice-edge error (IIEE), a user-relevant verification metric defined as the area where the forecast and the "truth" disagree on the ice concentration being above or below 15%. The IIEE lends itself to decomposition into an absolute extent error, corresponding to the common sea ice extent error, and a misplacement error. We find that the often-neglected misplacement error makes up more than half of the climatological IIEE. In idealized forecast ensembles initialized on 1 July, the IIEE grows faster than the absolute extent error. This means that the Arctic sea ice edge is less predictable than sea ice extent, particularly in September, with implications for the potential skill of end-user relevant forecasts.

  17. Loss of sea ice in the Arctic.

    Science.gov (United States)

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2009-01-01

    The Arctic sea ice cover is in decline. The areal extent of the ice cover has been decreasing for the past few decades at an accelerating rate. Evidence also points to a decrease in sea ice thickness and a reduction in the amount of thicker perennial sea ice. A general global warming trend has made the ice cover more vulnerable to natural fluctuations in atmospheric and oceanic forcing. The observed reduction in Arctic sea ice is a consequence of both thermodynamic and dynamic processes, including such factors as preconditioning of the ice cover, overall warming trends, changes in cloud coverage, shifts in atmospheric circulation patterns, increased export of older ice out of the Arctic, advection of ocean heat from the Pacific and North Atlantic, enhanced solar heating of the ocean, and the ice-albedo feedback. The diminishing Arctic sea ice is creating social, political, economic, and ecological challenges.

  18. The South China Sea Deep: Introduction

    Science.gov (United States)

    Wang, Pinxian; Li, Qianyu; Dai, Minhan

    2015-12-01

    The South China Sea (SCS) has increasingly become a global focus in ocean research and hydrocarbon explorations. Over the last two decades, at least 17 international cruises including two ODP/IODP expeditions were conducted in the SCS, and more than 2000 exploratory wells were drilled (Wang et al., 2014a). While its sedimentary basins on the continental shelf and slope are explored for offshore resources, the deep basin below 3500 m in depth that overlies the basaltic oceanic crust preserves the key to understanding their formation and development. In order to better understand the life history and functional system of the marginal sea, a major research program "Deep Sea Processes and Evolution of the South China Sea", or "The South China Sea Deep" for short, was launched in January 2011 by the National Natural Science Foundation (NSFC) of China. This venture represents the first ever large-scale basic-research program in ocean science in the country (Wang, 2012).

  19. The microwave scattering characteristics of sea ice in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    LIU Meijie; DAI Yongshou; ZHANG Jie; ZHANG Xi; MENG Junmin; ZHU Xiuqin; YIN Yalei

    2016-01-01

    Microwave remote sensing has become the primary means for sea-ice research, and has been supported by a great deal of field experiments and theoretical studies regarding sea-ice microwave scattering. However, these studies have been barely carried in the Bohai Sea. The sea-ice microwave scattering mechanism was first developed for the thin sea ice with slight roughness in the Bohai Sea in the winter of 2012, and included the backscattering coefficients which were measured on the different conditions of three bands (L, C and X), two polarizations (HH and VV), and incident angles of 20° to 60°, using a ground-based scatterometer and the synchronous physical parameters of the sea-ice temperature, density, thickness, salinity, and so on. The theoretical model of the sea-ice electromagnetic scattering is obtained based on these physical parameters. The research regarding the sea-ice microwave scattering mechanism is carried out through two means, which includes the comparison between the field microwave scattering data and the simulation results of the theoretical model, as well as the feature analysis of the four components of the sea-ice electromagnetic scattering. It is revealed that the sea-ice microwave scattering data and the theoretical simulation results vary in the same trend with the incident angles. Also, there is a visible variant in the sensitivity of every component to the different bands. For example, the C and X bands are sensitive to the top surface, the X band is sensitive to the scatterers, and the L and C bands are sensitive to the bottom surface, and so on. It is suggested that the features of the sea-ice surfaces and scatterers can be retrieved by the further research in the future. This experiment can provide an experimental and theoretical foundation for research regarding the sea-ice microwave scattering characteristics in the Bohai Sea.

  20. Seasonal sea ice changes in the Amundsen Sea, Antarctica, over the period of 1979–2014

    Directory of Open Access Journals (Sweden)

    S. E. Stammerjohn

    2015-06-01

    Full Text Available Abstract Recent attention has focused on accelerated glacial losses along the Amundsen Sea coast that result from changes in atmosphere and ocean circulation, with sea ice playing a mediating but not well-understood role. Here, we investigated how sea ice has changed in the Amundsen Sea over the period of 1979 to 2014, focusing on spatio-temporal changes in ice edge advance/retreat and percent sea ice cover in relation to changes in winds. In contrast to the widespread sea ice decreases to the east and increases to the west of the Amundsen Sea, sea ice changes in the Amundsen Sea were confined to three areas: (i offshore of the shelf break, (ii the southern Pine Island Polynya, and (iii the eastern Amundsen Sea Polynya. Offshore, a 2-month decrease in ice season duration coincided with seasonal shifts in wind speed and direction from March to May (relating to later ice advance and from September to August (relating to earlier retreat, consistent with reported changes in the depth/location of the Amundsen Sea Low. In contrast, sea ice decreases in the polynya areas corresponded to episodic or step changes in spring ice retreat (earlier by 1–2 months and were coincident with changes to Thwaites Iceberg Tongue (located between the two polynyas and increased southeasterly winds. Temporal correlations among these three areas were weak, indicating different local forcing and/or differential response to large-scale forcing. Although our analysis has shown that part of the variability can be explained by changes in winds or to the coastal icescape, an additional but unknown factor is how sea ice has responded to changes in ocean heat and freshwater inputs. Unraveling cause and effect, critical for predicting changes to this rapidly evolving ocean-ice shelf-sea ice system, will require in situ observations, along with improved remote sensing capabilities and ocean modeling.